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A BRIEF MANUAL 



PSYCHOLOGY 
DEMONSTRATIONS 



TO ACCOMPANY AS ILLUSTRATIVE 1\LATERL\L 
AN ELEMENTARY COURSE 



IX 



THE PSYCHOLOGY OF THE OTHER-ONE 



BY 
MAX F. MEYER 

Prof('Ssor of ExpcriDicnfal Psychology 
I'ji the Uiiiversiiy of Missouri 



(Cnlumhia, fHisaoiiri 

THE MISSOURI BOOK COMPANY 
PUBLISHERS 






Copyright 1922 
The Missouri Book Co. 



HAY -8 72 

©n!.A6S1805 



PREFACE 

This book has not been entitled either ''psychological 
experiments ' ' or ' ' psychological laboratory exercises ' ' be- 
cause it does not offer either that Avhich is impossible 
or that which but few college students need. 

It is impossible to teach anybody how to open up — by 
experiment, like a Galileo — into an unexplored region 
of the world new avenues of understanding. One can 
"teach" onl}^ that which is ''already known." Experi- 
ments can not be taught. They must be invented. 

To teach — thru exercises — how to take measurements 
by the skilful use of existing apparatus, is indeed })os- 
sible. But the demand for that instruction in measure- 
ment is relatively small among beginners, in psychology 
as in any science. And for advanced students who spe- 
cialize in psychology .there is no dearth of good labora- 
tory manuals. 

This book is not intended to be used alone, but only as 
an auxiliary — and a rather essential auxiliary — to the 
author's text-book, Psychology of the Other-One. 

No text-book in any science can rely totally on the 
student's ability to illustrate the theories taught — and a 
text-book ought to teach scientific theories! — bj^ using 
as illustrative material only his previous life experience. 
Therefore grapliic illustrations are used in texts and 
demonstrations in class rooms. 

It is well known, for example, in anatomy, that the de- 
moiislrative value of a di^-'sc'tion is grentor when the 

(1) 



Z PREFACE 

student applies his own hands than when he is a mere 
onlooker at a dissection made by the demonstrator. 

This book will help that student who uses the author 's 
introductory text, to apply his own hands to the demon- 
stration of certain not cj[uite ordinary experiences with 
other ]Deople (not with his consciousness). No demon- 
stration has been included merely because of its value 
as a curiosity. No illusion is included merely because 
it is an illusion. All these demonstrations illustrate 
and thereby further clarify the theories of which the 
text is composed. Any demonstration which has no such 
definite relation, has been rigorously excluded no matter 
how much the omission may hurt the book in the eyes of 
him who looks for "what is customarily included." 

Like the Psychology of the Other-One this book is 
written for the use of college freshmen and shows inci- 
dentally with what aims the elementar}^ (beginners') 
course in psychology has been taught in the University 
of ]\Iissouri for more than two decades. 

Max F. Meyer 
The University of Missouri 



Iniroductorij Advice. 

The student should, at the begiiiiiing of the course hi 
the Psychology of the Other-One, choose a partner on 
whom to make the demonstrations enumerated below. 
It is true that he can make some of these demonstrations 
on his own bocV, asking* himself the questions and an- 
swering them himself. For example, working with the 
color-wheel, he can ask himself whether the disk deserves 
to be called colorless. But he can not easily measure 
his own reaction time or run a maze and at the same time 
keep the records required. 

All the demonstrations given here can, and preferal)ly 
should, be made on the Other-One. This is not a course 
in introspective psychology. The famous warning 
''Know Th^^self" really means: Know the other fel- 
lows, including in this knowledge the opinion which they 
hold of 3''0U. 

In making the demonstration, follow the advice given 
in this manual ; but also compare the text-book ; and 
whenever you have exhausted your resources, do not 
hesitate to ask the instructor's advice. He is not your 
enemy. 

In writing up your demonstrations, use common sense. 
Avoid unnecessary words. But write — make this your 
standard to judge by — enougli to feel satisfied that il' 
yon sliould read your notes again after a year's interval. 
Ilic whole demonstration would again be clear to >()n. 
Kemember, — be bi'ief. That ej)0('h is i)ast when teachers 

(3) 



4 PSYCHOLOGY DEMONSTRATIONS 

based the marks tliey gave to students on the weight of 
the paper filled by them during an examination period. 
You will be graded on the basis of tests proving what 
you have accomplished, not on how much you have writ- 
ten in your note book or on a test paper. Do not copy 
in 3^our note book sentences from this manual or from 
your text. 

Do not misunderstand what has just been said as 
meaning that you should abstain from writing when 
you study. On the contrary, no better advice can be 
given to you than to answer the cpiestions which you find 
printed in the back of the text-book, not only orally, but 
in writing. 

I. The Time of a Beaction^ Simple or Choice. 

The reaction time is recognized to be one of the most 
fundamental facts with which the psychology student 
must be familiar. In order to familiarize yourself wdth 
it, you will measure your partner's reaction time in the 
case of a simple reaction and also in the case of a choice 
reaction. 

When reading of "choice," do not think of anything 
subjective like a powder of the soul or a mysterious en- 
tity like the one represented by the "deus ex machina" 
on the Greek stage. Choice means that the stimulation, 
and with it the response, ''varies from time to time," as 
you will vary it here. 

There are very many time measuring instruments 
which have been invented for the measurement of du- 
rations of time from a few seconds down to a thousandth 
part of a second. That instrument which you w^ill use 
here was invented bv Professor Sigmund Exner of the 



REACTION TIME 5 

University of Yienua and called by him "neuramebi- 
meter," that is, "nervous flux recorder." See sketch 
on page 46 of your text. 

Tliis instrument measures the reaction time in hun- 
dredths of a second. It is very simple, fairly fool-proof, 
and gives you a chance to learn incidentally about the 
method of registering a momentary event by a mark 
made on a smoke covered and moving surface. 

Take out the glass slide and smoke it on its proper 
surface over a candle. After taking one record, you re- 
move the glass again and reinsert it with ends exchanged, 
so that one smoking will permit you to record two re- 
action times. After that you wipe the glass clean with 
a towel. In order to smoke the glass, take one end be- 
tween your fingers, touching with your fingers the 
ground edges and thus leaving the surface to be smoked 
virtually free. Steadily move the glass in a quick motion 
lengthwise back and forth thru the flame. Remember 
"move." Do not hold it still. You do not want to heat 
the glass and burn your fingers. Be patient and soon 
you will see the surface covering itself with a uniform 
gray layer of fine soot. . Then take hold of the other end 
and smoke the place which (in order to save your fing- 
ers) you have not yet moved thru the flame. 

Remember "thru the flame," not above the flame. 
But do not touch the wick, or you will get candle grease 
on the glass. Remember "gray." You do not want 
the glass black, for you do not want to provide more 
work for the laundry than is unavoidable. 

"When the smoked glass slide is in place, with Ihe vi- 
In^ating spring bent sidewise and resting against the big 
])in. see to it that the writing point lias neither too much 
nor too little friction on the c'lass. 



6 PSYCHOLOGY DEMONSTRATIONS 

Now seat your partner comfortably on a chair (s't 
down yourself, too) and tell liim to touch (not to weight) 
the button with the index finger of his better hand. Make 
him close his eyes and instruct him to press down the 
button with the greatest possible speed as soon as he 
hears the rather low and dull tone of the vibrating reed, 
the big steel spring. Give him first a little practice in 
doing this, before inserting the smoked glass, and thus 
without taking any record. 

When you pull the hook, be sure that you hold it firm- 
ly between the index finger and the thumb. Practice it, 
pulling the whole slide entirely from its bearings. It 
must then be securely held by you in the air and not 
drop on the fioor. 

Next to the glass the most breakable part of the in- 
strument is the tiny spring point which writes on the 
smoked surface. Never move the slide hackwards with- 
out being sure that this point is safe (button down) 
while you push the slide back. 

You do not want ever to surprise your partner. We 
do not in psychology demonstrations play tricks on each 
other any more than we use magic. Therefore, two or 
three seconds before pulling the hook (varying this time 
a little) you say "Ready," so that he may get ready 
and avoid surprise. 

If you do not know how long two or three seconds last, 
look at the pendulum of the laboratory clock. It swings 
from one side to the other in about two-thirds of a sec- 
ond. Three swings make two seconds, six swings four 
seconds, and so forth. 

Test your partner and count the number of waves in 
the smoke. Eacli wave, from valley to valley, lasts one 



REACTION TIME / 

hundredth of a second. If the hist visible wave is incom- 
plete, count it one provided j^ou see more than om^-lialf 
of it. If less, do not count it. 

If yon count less than ten waves, disregard that tesr. 
Either one of two possible mistakes has occurred. Your 
partner, instead of reacting to the tone signal, nuiy 
simply have become impatient witli watchful waiting 
after hearing you say ''Ready." Or your partner did 
not follow yonr order barely to toiicJi the button, but 
weighed his hand on it, letting it rely on the friction 
between the big spring and the pin. As soon as you be- 
gin to 'pull, that friction changes from rest friction to 
motion friction. The latter, as you learn in physics, is 
very much less powerfnl. Therefore now^ by mere gravi- 
ty yonr partner's hand and arm (even if — imagine — 
the}^ had been cut off at the shoulder) would push the 
button down. But you do not want to measure the re- 
action time of gravity working against friction. A nor- 
mal human reaction time can not be rednced to less than 
ten hundredths of a second. 

Take fifteen tests. Write down in your note liook 
the fifteen nnmbers counted as well as their average. 
Learn at this time that you will never find men of 
science satisfied with being told an average alone, with- 
out any indication of how those actual test values varied 
from which that average was computed. Don't use 
decimals in computing the average. Choose tlu^ lu^arest 
integer. 

If you are interested in knowing how you conhl save 
paper space hy substituting for tlie many test valnes a 
mere statement of the average deviation, ask the insirne- 
tor liow to compute that deviation. But tliis is ik.i re- 
quired. 



b PSYCHOLOGY DEMONSTRATIONS 

Now ask your partner what average reaction time he 
found when he tested you. Notice how people may dif- 
fer. 

After having thus measured your partner's simple re- 
action time, measure his time of a choice reaction. Pro- 
ceed in exactly the same way as with the simple reaction 
time, with the following additions and exceptions. 

Put the index finger of his second best hand on the 
button of a contact key which will cause the striking of 
a gong when the button is pushed down. Then instruct 
your partner to get ready to react with either hand, but 
to react with the second hand alone whenever you say 
' ' Gong ' ' and with the best hand alone whenever you saj^ 
"Noo" (for neuramebimeter). 

Make for your own use, secretly, a list of fifteen times 
the word "gong" and fifteen times the word ''noo, " 
mixed at random. 

Pronounce your word very quickly and very distinctly 
at the very moment when you pull the hook. You may 
have to pull the slide now more slowly than in taking 
the simple reaction time, and you may have to pull it 
clear out of its bearing in order to get all the waves 
written on it. 

When you hear the gong striking altho you did not 
say "Gong," make a cross in your list indicating an 
error. 

If your partner should raise the writing point of the 
neuramebimeter and thereby interrupt the wave line 
altho you did not say ' ' Noo, ' ' save the time of counting 
the waves. Simply make an error cross in your list. 

You are likely to get fewer than fifteen correct re- 
action times. But they will suffice for this demonstra- 
tion. 



REACTION TIME 9 

Ask your partner, for comparisoii, ^vliat aA^erage choiee 
reaction time he found when he tested yon, and also 
what number of errors he found Avith you. Notice 
first, wliether all people are equally fast; and second, 
whether they are ecpially apt to fall into errors. 

II. The Fonnation of a MultipJe Ha'bil of the Serial 

Type. 

Warning : Do not go about in the laboratory looking 
at the mazes used by other pairs of students. Seeing 
them spoils your oavii Avork completely. 

Our text (p. 124) has taught us that all types of habit 
formation can be reduced to one simple and fundamental 
type. Tayo stimuli must be applied Avith no great time 
interA-al betAA^een them. (The longer that interA^al, tlie 
weaker the habit : ' ' 10 seconds stimulation interA^al ' ' — 
''very AA^eak effect.") Remember: there are always two 
stimuli. 

The tAA'O (complex) neiwous currents are serA^ed hy a 
longer and common path. Each of the currents is also 
serA^ed by a shorter path AA^iich each of the tAvo functions 
(either reflexes or old habits) possesses separately from 
the other function. The habit formation consists in the 
reduction of the resistance of that longer and common 
path. Compare tlie figure of page 124 of your text. 

The change occurring in the neiwous system, as de- 
scribed in the text more fully, can be stated in brief and 
more abstract form as folloAvs, in tAVO stages (wliii-li. 
liowcA-er, are not successi\'e in fact). 

Warning: Do not confuse ''susceptibility" Avitli "coii- 
diictivitA'." Consult the index of yowv Icxt. 



10 PSYCHOLOGY DEMONSTRATIONS 

First Stage. 

Condition : The black lines suffer a double influeiice 
because of the double stimulation. 

"Limit" which this influence approaches (tho never 
reaches) : The resistance of the black lines approaches 
zero. 

Conclusioji : A current coming from Sa now divides 
(with ever increasing approximation) in halves, that is, 
equallj^, at Sa. 

Assumption made previously on broader grounds than 
the present necessity: The ''higher" neuron Sa Sal 
is more susceptible than the "lower" neuron Sa MJ. 

Total Conclusion: Finally all the current would go 
from Sa upwards to the higher center. Nothing then 
goes from Si to the right. (Ps3^chology of the Other- 
One, page 127, line 4.) 

Second Stage. 

Condition : The double stimulation is always applied 
more strongly at Sb than at Sa. 

Conclusion: The resistance from Ma\ to Mb is more 
quickly reduced than the resistance from Mat, to Ma. 

Final Conclusion: Most (or aU) of the current from 
separate stimulation of Sa now goes (I) from S^i up- 
wards and (II) from Mab down to the right, to Mb. 
(Psychology of the Other-One, page 127, line 6.) 

It is self-evident that the changes in the nervous sys- 
tem here in C[uestion must be the greater, the stronger 
and the longer the stimulation. ]\Iany stimuli either 
can not be strengthened or cannot be prolonged without 
ceasing to be what they are to be. For example, a word 



MULTIPLE HABIT H 

sound can not be prolonged to last a niimite,— that would 
no longer be that word but a howl. Length of the 
stimulation then can be secured only by fr.equent repeti- 
tion of the stimulus. But the student must remember 
that the total duration of the stimulation is here the de- 
termining factor. There is no such thing as a fundamen- 
tal '4aw of frequency" in habit formation. That is only 
a corollary of the condition of length. 

Neither is there any such thing as a fundamental ^'law 
of effect" in habit formation, altho it has spooked for 
years in many psychology texts. Quite apart from the 
fact that an explanation by effect would be teleology, 
since science explains by causes,— that '4aw of effect" 
is only a corollary of the condition that there must be 
two sensory-motor functions (reflexes or old habits). 
One stimulus alone cannot create a variation of its 
response. The second response, that contained in the 
second sensory-motor function, really is Avhat those texts 
vaguely refer to when talking of ''the effect." 

A simple habit like the one represented by the figure 
on page 12i of the text is acquired hy human beings so 
quickly that the process of forming the habit can not 
easily be demonstrated as being a particular ''function 
of time." With animals this demoiistration is possible 
even in a simple habit. But our fellow men interest us 
more than animals. Experiments to discover what that 
mathematical ''function of time" Avas, were therefore 
first made — by Ebbinghaus — on multiple, not on simple 
habits. The experiments l)y El)l)inghaus on the for- 
mation of multiple speech liabits ai-e now regarded as 
classic. He learned to recite a series of ten or twenty 
nonsense syllables and therel)y determined "tlie learning- 



cui've. 



12 



PSYCHOLOGY DEMONSTRATIONS 



Eemember, that tlie only reason why, in determining 
the learning curve, one did not experiment with a single 
simple speech habit, was the fact that in a human l^eing 
such a habit is often acquired in ''no time." 




FIFTH 
SOUND 



FIFTH SIXTH SIXTH 

SPEECH SIGHT SPEECH 



Use the figure to make clear to yourself that learning 
a series of nonsense syllables is nothing other than a 
multiple habit. 

The fifth word-sound is most readily responded to by 
pronouncing the fifth word ; but there is the sight of the 
sixth word which is responded to by the pronunciation 
of the sixth word. The sentence just finished describes 
the process of habit formation. 

As soon as the habit is strong enough, the two middle 
ones of the four external factors have dropped out com- 
pletely. As long as they have not dropped out complete- 
ly, the habit is still weak. 

The habit in its full strength functions with only the 
first and fourth external factors. That is, the fifth word- 
sound is directly responded to by the pronunciation of 
the sixth word. 

(Look at the figure! — At the beginning of the series, 
substitute "first" for ''sixth" in the third and fourth 
factors. Substitute in the first and second factors "in- 
vitation sound" for "fifth sound" and "restating the 
invitation sound" for "fifth speech.") 



MULTIPLE HABIT 



13 



Experiments to discover the time fiinetioii for multi- 
ple habits of actions other than speech actions have been 
made in later years especially in America, most fre- 
quently by letting an animal run a maze.- You will 
demonstrate here the formation of a multiple habit by 
letting your partner run a maze. 




OD 



M^ 



^6 



^6 



Look at the figure !— You ^ee there the first factor in- 
dicated by a double circle. This double circle is used 
as a symbol for a sitnation presenting, after various pre- 
vious maze turns and splits, more than one possibility of 
proceeding in locomotion. You can now proceed by 
taking either the continuation to the right or that to 
your left. If there is anything in the situation which de- 
termines your taking the good tunnel, there is nothing 
further to say. 

If you take the bad tunnel, you run into a blind alley 
which turns you back to its own entrance. The symbol 
indicating the second factor in the figure represents 
your action of entering and leaving behind that blind 
alley. 

The third factor is indicated by a composite of the 
symbols of the first two factors. That is, the stimulation 
consists of the splitting tunnel ]')lus •'Ihc sliuinlalion 



14 PSYCHOLOGY DEMONSTRATIONS 

resulting from" (popularly speaking, ''the experience 
of") going into and out of the blind alley. 

The fourth factor is indicated in the figure by a curve 
bending in the other direction, leading to a double arrow 
bead, which reminds us of the possibility of unblocked 
progress. 

The last four paragraphs together describe the process 
of habit formation. The habit in its full strength func- 
tions with only the first and fourth external factors. 
That is, the situation — of meeting, after various previous 
maze turns and splits, this split of the tunnel — is now 
directly responded to by taking the turn into the good 
tunnel. 

After having made all this clear to your partner, you 
ask the instructor to give you one maze and j^our part- 
ner a different maze. No pictures of these mazes are 
shown in this manual because — you remember — seeing 
the mazes in advance spoils your demonstration. One 
of these mazes is a famous plaything of royalty, the so- 
called Hamilton court maze, but with some modifications. 
All the shunts have been converted into blind alleys. 
You then have nine different habits to form in order to 
run the maze without being lured into any blind alleys. 
The other maze is of a design that has been used fre- 
quently for experiments with animals. You have to 
fo^m sixteen different habits in order to avoid all the 
blind alleys. 

You now place your maze well covered with a cloth 
before your partner. Your partner places his maze 
well covered before you. 

If you want to look at your maze, do not luicover it 
without being sure that your partner will not see it. 
You have to uncover it in order to write down in your 



MULTIPLE HABIT 



15 



note book first a column of numbers from 1 to 16 (or to 
9) and then to the right of eacli number in a second 
column the letter R or L, according as the good turn is 
either right or left. In a further column (3^ou must 
provide for several more) you will later make a cross 
whenever you see your partner make a dad turn. 

Now get your watch ready, make your partner close 
his eyes, uncover your maze, put his finger in the center, 
and when you like the position of the hands of your 
watch, say ' ' Start. ' ' 

At the instant your partner drops out of the maze, 
note down the time. Then cover your maze and only 
then permit him to open his eyes. 

Now couA^ert minutes and seconds all into seconds and 
write that number above the proper column. Below the 



<^/oo 



Grrors 7 S 6 4 2 3 > 



column write the number of crosses, that is, bad turns, 
errors. You need these entries, because at home you will 
make a graph of tlie running of your maze hy your part- 
ner, like the sample shown. 

You now take a rest by letting your partner make you 
run his maze once. 



16 PSYCHOLOGY DEMONSTRATIONS 

Then you make him run your maze once again ; and so 
on alternately until you have seen your partner run j^our 
maze without an error three times in succession. 

Answer this question : Why does the preceding para- 
graph insist upon three times in succession'^. "Why is 
"once without an error" not enough to stop? Discuss 
then, the demonstration being finished for both, with 
your partner the questions whether he is more clever 
than you or the reverse, and whether one of the mazes 
is more difficult to run than the other. (Both mazes are 
now open to your inspection.) 

You must after that — you should not do it before — 
ask the instructor whether with animals one kind of 
maze has been found to be easier than the other. 

If your previous conclusion seems to be discrepant 
with his answer, read chapter XVlI of your text in order 
to straighten the matter out. 

Finally compare your learning curve with the learning 
cur\^e on page 132 of your text. Tell whether it is the 
same or a different type of curve, and what makes it 
either alike or different. 

III. The Threshold in Estimatmg Weights. 
First Part 

It often happens in life that you have to apply your 
body to something multiple which, from case to case, 
becomes either increasingly difficult or increasingly easy. 
With increasing difficulty, it is clear that you should 
then pass thru some cases where you saj^ ^'It is more or 
less guess work." Those cases you call the "threshold." 
You are, so to speak, passing out of the chamber of suc- 
cess. But vou have not vet left that chamber behind 



THRESHOLD IN ESTIMATING WEIGHTS 17 

you,— you are still "on its tlireshokl. " Passing to fur- 
ther cases in the same direction, it becomes '^a mere 
g'uess. ' ' The chamber of success now is at a distance : 
You have left behind you the threshold, figuratively. 

Going from case to case in the other direction, too, you 
pass thru the threshold. You then say ''It no longer is 
a mere guess; but there is no certainty yet." 

Do not, then, think of the threshold as a dividing line. 
It is a dividing region, just as the threshold of your bed 
chamber is not an abstract geometrical line, but a board 
of considerable width, enough to remain standing on. 

The threshold, in a more abstract geometrical sense, 
has often been defined statistically by the numerical 
probability of an error being just one-half, that is, the 
probability of success being equal to that of failure. 
This- by the Avay. You will not, in this demonstration, 
have to consider further this abstract threshold. 

You will now demonstrate in the concrete Avhat is 
meant by the threshold. You will make the human race 
appl}" itself to estimating weights. For convenience's 
sake you will here restrict yourself to that part of the 
human race made up of your partner and yourself. You 
need not hesitate thus to restrict your demonstration. 
You are not here expected to make a contribution to 
science by discovering the exact location of that thresh- 
old — that has been found out already with sufficient ac- 
curacy by others. 

You will then here form a closer partnership than be- 
fore with 3^our partner. You will ask your partner to 
lift one after another the seven wooden weights, Avhich 
look very mucli alike, and arrange them (juickly (in fif- 
teen or twenty seconds) in an orderly series from the 
heaviest to llic lightest, innnediatcly yonr jiartiun" will 



18 PSYCHOLOGY DEMONSTRATIONS 

ask you to lift them in succession and make any change 
in their order that seems to you necessary. Then again 
your partner, and again you, and again your partner, 
and so on alternately, will do the same until you both 
reach an agreement. 

Do not complain to the instructor that you can not 
reach an agreement, that the one of you regards a weight 
as heavier which the other regards as lighter. There 
are many situations in life where we absolutely have to 
agree. This is one. You should have selected a more 
congenial partner. It is now too late. You have to 
make the best of your choice. You have to compromise. 
How — that is your own business. 

As soon as you both have settled the matter and the 
weights appear in what you both regard as the final ar- 
rangement, ask for a balance and weigh each weight in 
full grams, writing the numbers down in a single column 
in your note book, carefully preserving the order from 
the heavy to the light. 

''In full grams" means "not using fractions." Use 
the nearest integer. The "nearest," not the next higher 
invariably nor the next lower either. 

These seven numbers now form six ratios, the first 
and second number the first ratio, the second and third 
number the second ratio, and thus to the sixth ratio. 

Now rewrite these ratios in terms differing by 1. This 
can easily be done by subtracting the "denominator" 
from the ' ' numerator ' ' and dividing by the difference 
thus 'found both the "numerator" and the "denomina- 
tor." For example, if you have 111 grams and 99 
grams, the difference is 12. Dividing 111 by 12 and tak- 
ing the "nearest" integer gives you 9 (because 111 :12 is 



THRESHOLD IN ESTIMATING WEIGHTS 19 

9% 2- ^11^^ dividing 99 by 12 gives you 8. So the 
ratio for this case is 9 : 8. 

After having written in a column the six ratios in 
terms differing by 1, mark all those ratios with a cross 
which are wrong, that is, in which the smaller term pre- 
cedes the larger term. Suppose you find then only one 
marked with a cross; record that ratio as surely being 
"within the region of the threshold." 

Suppose you find two or more ratios marked with a 
cross; select the one that has the smallest terms. For 
example, if the ' ' wrong ' ' ratios are 21 : 22 and 53 : 51, 
record 21 : 22. It is clear — is it not ? — that if you, the 
whole human race co-operating, already make a mis- 
take in the case of the weight difference of one twenty- 
first, your estimation is already here becoming more 
or less guess work and will be still more so with a 
difference of one fifty-third. So you record, if you 
record any one ratio, rather that with the smallest terms 
differing by 1. The ratio with the smallest terms is the 
most interesting one from the practical point of view. 

Thus you have made a concrete demonstration of the 
threshold of the human race in estimating weights tliat 
look alike. Never mind • that j^our result is not very 
accurate. How to proceed in order to get a very ac- 
curate measurement, is a question wliicli does not now 
and here confront you. 

But suppose that none of the six ratios was wrong. 
Well — tliat was l)ad luck for you. You thereby learii 
that in psychology demonstrations it fre((uently hap- 
pens that the ''errors" are tlie onh/ events tluH are 
interesting. Do not conelude tluit you are with yoni- 
weiglits ali'each' Ix'xond the thresliold reuion. on ihc 



20 PSYCHOLOGY DEMONSTRATIONS 

side of certainty of judgment. Believe the author of 
this book when he tells you that you are not. 

Of course, it does not follow that therefore you mr.st 
intentionally now and then apply yourself in the wrong 
way. But it does follow that you must not by any kind 
of trick or jugglery (for example, by secretly weighing 
and marking the weights in advance) try to cheat the 
instructor. In such a case you do not cheat the instruc- 
tor, but you cheat yO'urself. You then, having no er- 
rors, have to ask the instructor to give you a new set 
of seven weights, and you and your partner have to 
make the demonstration all over, until you have some 
error. 

If, however, you have used no trick whatsoever, and 
nevertheless your ratios are all right, you simply have 
had 'bad luck (that often happens in this world) and 
you have to ask the instructor for a different set of 
weights and make the demonstration all over. 

Second Part 

The instructor will now give you two wooden weights 
considerably differ ing in size. You notice that these 
weights have holes on top. You will then fill one of 
them with scraps of lead until your partner and you 
admit that they are now as equal in weight as you can 
mutually agree on. 

Remember that nobody has asked you to use any 
trick, for example, to close your eyes and balance these 
weights on the tip of your nose. You apply your body 
to these weights as naturally as you apply it to pick- 
ing up a chair in one corner of the room and setting it 
down in another corner. Use only one hand always. 



THRESHOLD IN ESTIMATING WEIGHTS 21 

AYhen von liave filled one of the holes to the top, 
do not hesitate to put a little paper box on the top to 
receive more of the lead scraps. After making tlie 
weights equal, you weigh them on the balance in full 
grams and compute the ratio in terms differing by 1. 

Now ask your partner the question: ''Is this ratio 
(much or little) above or below the threshold which we 
found in the first part of this demonstration T ' — Explain 
to your partner what is meant by "above" or "below" 
the threshold. "Above" means in this case that the 
ratio terms are smaller than . those of the threshold. 
"Below" means that the terms are larger. 

Further ask j^our partner what his experiences (be- 
fore and after) were when, in the middle of a long 
journey made without changing the train, the locomo- 
tive was taken off and replaced by a much stronger 
acting engine. Then ask him whether he suspects that 
his muscle contractions applied to the one and to the 
other weight, might be comparable to those two locomo- 
tives, and whether his experiences might be comparable 
to those on that train before and after the change of 
locomotives. Could he have had similar experiences if 
instead of a change of locomotives something had hap- 
pened to the train itself f What? Ask your partner 
to read what he finds on page 148 of his text on the 
kinesthetic sense. Ask him whether that helps him to 
talk about his experiences with the weights. 

AVhat" happening to the train itself would be directly 
comparal)le to filling the holes with lead scraps? And 
what are (1) the experiences wliich wouUl then be 
equalized on your railroad journey, and (2) those ex- 



22 PSYCHOLOGY DEMONSTRATIONS 

periences which are then equalized on your weight lift- 
ing enterprise? (Refer to page 148 of your text.) 

Try whether you can avoid "changing the locomo- 
tives" by closing your partner's eyes and hanging each 
weight a little while from a string looped over his out- 
stretched finger instead of permitting him to pick up 
the weight. 

Finally read in your text all the references which 
you find in its index under "illusion" and tell what 
relation they have to the second part of this demonstra- 
tion. 

IV. The Soimd Localizing Reflex. • 

You want to become familiar with the fact that your 
basic action equipment, received thru heredity, is your 
eciuipment with reflexes. Get then a concrete idea of 
the sound localizing reflex by finding out whether your 
partner's success in using sound localizing hahits is 
conspicuously improved by the additional function of 
this reflex. Compare page 180 of your text. 

Recall what you find on page 194 of your text about 
the dimension or dimensions of this reflex. 

You are going to use telephone clicks. Wi'l your 
partner be able to use the localizing habit described on 
page 194 of your text? The existence of what other 
localizing habits seems probable to you? F,3r example, 
do you believe that you might possess a habit h"ke this : 
Calling a rather strong click "front" instead of strong, 
calling a rather weak click "back" instead of weak, 
and a medium click "above"? 

Remember during the whole demonstration that you 
want to discover if, in comparison with that success 



SOUND liOCALIZlNG REFLEX 23 

which depends on his habits alone, the reflex improves 
your partner's success in localizing. Remember that 
the improvement can be demonstrated only by the per- 
centages of errors, and that, if there are no errors at 
all, there will be no percentages to compare. Tell your 
partner, therefore, that you do not intend to prove that 
he is clever enough or unable to get thru without errors, 
that on the contrary the errors are the only valual)le 
part of the demonstration. Tell him that you have, 
therefore, no objection to his reciting to himself, silent- 
ly, anything he may wish to, while you are giving the 
clicks. 

Ask the instructor to give you a printed record blank. 
On this blank you find 81 squares in nine rows and nine 
columns. The rows correspond to the nine stimuli Right, 
Right-Back, Right-Front, Back, Above, Front, Left- 
Front, Left-Back, and Left. Inform your partner that 
these will be the only stimuli ever given and that, there- 
fore, he need not ever reply in any words but these. 
The judgment pronounced by your partner will be re- 
corded by you by making a little cross in the proper 
column, but exactly in that square of the column which 
is located in the row corresponding to the stimulus 
given in that case. The question of ''right or wrong'' 
does not arise in this recording. 

Remember, you never want to suri)rize your partner, 
but you prepare him by a ''Ready" signal. Being sure 
that your partner's eyes are closed, you set the tele- 
phone, bit the key hard with your finger so tlint the 
noise of hitting serves as "Ready" signal, niid two or 
three seconds later raise your finger. Tlie bi-enk in ilie 
electric current causes the click in i\\o telephone. \(mv 
partner pronounces his judgment, and you i-crord il. 



24 PSYCHOLOGY DEMONSTRATIONS 

Continue this, irregularly varying the location of the 
telephone^ until you have ten records in each of the nine 
rows, — a total of 90 judgments. 

Never repeat the click, even tho your partner may tell 
you that he was not sure of its location. Recall to him 
that it is his very error, and not his being sure, that in- 
terests you. 

Your partner will then ask for a second record blank 
and will make the same demonstration on you. You 
may, however, both of you, divide the whole task and 
alternate two or three times, being now subject, now 
demonstrator, now subject again, and so forth. 

Now translate the records from your squares into the 
followingr summaries. 



Lefts (L, LF, LB) regarded as Rights (R, RB, EF) times. , ^ , , 

Total. 



Riglits (R, RB, RF) regarded as Lefts (L, LF, LB) ... .times. 

Fronts (F, RF, LF) regarded as Backs (B, RB, LB) or Ahove . .times. "^ 

( Total. 
Backs (B, RB, LB) regarded as Fronts (F, RF, LF) or Above, .time-s. C 

Above called Fronts (F, RF, LF) or Backs (B, RB, LB).. times. 

Above called Rights (R, RB, RF) or Lefts (L, LB, LF).. times. 

Above judged correctly - - - - - - - - - times. 

Then draw a final conclusion as to whether the reflex 
has shown its • influence or not. Also state what your 
record shows, if anything, concerning the ''habit ques- 
tion" raised above in the third paragraph of this chap- 
ter. 

V. The Reflex of Adjusting the Eijehall. 

You know that it has an effect on you, calling forth 
your bodily reactions, when the Other-One turns his 
eyes on you. In this respect we can speak of a local- 



ADJUSTING THE EYEBALL SO 

izing action performed by the Other-One with his eyes. 
But this is a localizing hahit developed out of an adjust- 
ing reflex. Read pages 188-189 and 193-194 of your 
text. 

The study of the sense organs as such is not neces- 
sarily a part of the psychologist's task. The physiolog- 
ist must study all the sense organs. The psycJiologist 
studies them only in so far as his defl^nition of psychology 
requires it. (Different psychologists diifer in their def- 
initions.) Read what you find about the definition of 
psychology in your text on pages 8-11, 405-408, 421, 
422. Read also the reference you find in the index of 
your text to ''higher senses". Do you see, then, any 
reason for familiarizing yourself with the adjusting re- 
flexes of the organ of sight ? What is the reason ? 

The reflex of adjusting the eyeball in its bearings is 
necessitated by the fact that the sensitive cells of the 
retina are very close together only in the central region. 
Things with small details (especially printed matter) 
can therefore act properly as stimuli only in that cen- 
tral region. Tliat is the reason why the eyeball is con- 
stantly moving. 

But it is a mistake to think that the stimulation is 
effective during the motion of the eyeball. Nature lias 
made a provision whereby the excitation coming from 
the retina during eye motion is completely deflected 
(probably by the very nervous current causing the con- 
traction of the eye muscles); so that there is virtually 
no reaction to the retinal excitation. (Understand what 
''deflection" means by using the index of your text.^ 

Thhik it over and answer the ((uestioii wIuMIum- \\w 
loss of this reaction dni'inu' eve movciuciil is a s-rious 



26 PSYCHOLOGY DEMONSTRATIONS ' 

one, or — possibly — even an advantage. What could 
your, partner call a thing stimulating his retina during 
the eyeball's motion? Would that name be of any 
help to him or to you in getting along in this world? 
Remember, in answering these questions, that the eye- 
ball is incapable of moving with a small angular ve- 
locity; that it always moves with a very great angular 
velocity. 

Further ask yourself of what significance the loss of 
the reaction to retinal stimulation during eye movement 
is for the theories, rampant until twenty years ago, 
which explained the great beauty of a smooth curve in 
comparison with an irregularly bent zigzag or scrawl 
by the greater ease of following one of these lines con- 
iinuously with the seeing eye. Why are these theories 
not found in recent books ? 

When your partner reads, he reacts only to the stim- 
lations occurring while the eyeball stops. Demonstrate 
these stops by asking your partner to read — very slowly 
and aloud— from an easy text about twelve or fifteen 
consecutive lines. Close to his text on the right you 
place a mirror and watch your partner's right eye in 
this mirror. Let your partner rest his head against a 
support which will virtually exclude head movements. 
Make a pencil mark every time an eye movement oc- 
curs ; but do not make a mark for the longer movement 
leading from the end of one line to the beginning of the 
next. 

It has already been said that you must make your 
partner read aloud, in order that you may be sure 
that he is really reading, — and reading properly, that 
is, in the way you want Mm to read. Tell him to make 



ADJUSTING THE EYEBALL 27 

a very conspicuous pause at the end of eacli line, bnt to 
make no conspicuous pauses at the punctuation signs. 

If the number of eye movements in a line is n, what 
is tlie number of stops'? Write down in your note book 
the number of stops which occurred in each of the lines 
read. Also measure and write down the length of the 
lines. Why the latter"? Also determine the average 
number of letters (and spaces) for each stop. 

Now cover the right and the left side of a printed 
line with paper (fastening it with clips), leaving un- 
covered onlj^ as many letters (and spaces) as you j':st 
found by computation. Choose as the center of this 
group of letters a conspicuous narrow one, for example, 
a f. Then tell joiiv partner to fixate with his eyes this 
central letter, and, while keeping his eyes perfectly stiV, 
to name all those letters which are clearly recognizable. 

What significance does it have if he names all or not 
all of the letters exposed? Does it explain any facts 
which you are familiar with or have heard about in 
connection with the manner people read? 

Do you know anything like it in human life outside 
of reading, even outside of the use of the sense of sight ? 
Do you find anything like it mentioned on page 227 of 
your text? What is it? 

YI. ReversiiKj One of the YisuuJ Localiziiiy l-icjie.res. 

You should first understand the purpose of this dem- 
onstration by reading pages 183 and 184 of your text. 
Ask the instructor to give you th(^ card ])i('tured on 
page 184 and a large total reflection ])i'isni. — hii-ge 
enough to look thi-u with both eyes at once. Ab)iiiit the 
card on the tal)h' and tlic prism lict'oi'c yonr partner's 



28 PSYCHOLOGY DEMONSTRATIONS 

eyes so that the card, when your partner looks at it 
thru the prism, appears perfectly natural with the num- 
bers from 1 to 16. 

A similar procedure would consist in using a mirror 
instead of the prism. But that would have the enor- 
mous disadvantage of forcing your partner to ^'look'^ 
(at the object handled) in one direction, toward that 
mirror, and to "handle" the object seen in an entirely 
different direction, where it really is. You would then 
not only reverse your partner's localizing reflex in a 
single direction, hut force him to acquire simultaneously 
a complexity of other very queer habits. Such a com- 
plexity would confuse you. As a matter of fact, a total 
reflection prism is nothing but a mirror, but it is a mir- 
ror which does not serve the purpose of looking at your- 
self, but of looking at other things without hreaking the 
line of sight angularly. 

Now give your partner the sixteen little squares w^ell 
shuffled, not in any order. Wait till the hands on your 
watch have a convenient position and say "Start". 

Do not accept your partner's work until the little 
squares have been distributed wdth sufficient accuracy 
so that each is properly placed, without conspicuously 
encroaching upon the area belonging to its neighbors. 
Then mark at once the time and reduce minutes and 
seconds all to seconds. 

Now give your partner a chance to put you to the 
same task. After that he must distribute the little cards 
again, you again, and so forth. Stop this finally when 
you notice that the time of performing the whole work 
drops from the preceding case to this last only quite 
inconspicuously, or even rises slightly by accident. 



REVERSING ONE OE THE REELEXES 29 

Quite aside from having demonstrated the tenacity 
of the original reflex, you have again demonstrated the 
possibility of breaking up a reflex, substituting for the 
original muscular action a different muscular action. 
And you have again the material for the construction 
of the learning curve. Show your partner's learning in 
a graph similar to the one you made in the second dem- 
onstration and follow again the instruction given in the 
last paragraph of the second demonstration. 

YII. Some Habits of Rhythm. 

This demonstration has to be continued for at least 
two months, altho it takes only a few minutes each week. 
It must therefore not be begun too late in the course. 

Your partner may have "rhythm". If you ask lum 
and he answers in the affirmative, ask him further ' ' what 
rhythms" he has. If he does not understand your c^ues- 
tion, read to him page 338 of your text. It is not very 
probable that he will assert that he already possesses 
the 5-stroke or the 7-stroke rhythm. Therefore 3^0 ti will 
do best to choose for your demonstration of the acquisi- 
tion of rhythm habits, the 5-stroke and the T-srroke 
rhythms. Make an agreement with your partner set- 
tling the question which of you shall learn the 5-stroke 
rhythm and which the 7-stroke rhythm. 

In order to be able to demonstrate in the e)id tiiat 
your partner has acquired a (weaker or stronger) 
rhj'thm habit, you must measure how well he Cc\ii per- 
form a certain act, which later will depend oi; tlie aid 
of that rhythm habit, at the present time without tliat 
rhythm habit. You will then later also measure how 
well li(^ can ])erfoi'm that same act (which lie mWI not 



30 . PSYCHOLOGY DEMONSTRATIONS 

practice meanwhile), and the difference will tell you 
whether he has acquired, weakly or strongly, that 
rhythm habit. 

Suppose your partner has chosen to be trained in the 
7-stroke rhythm. You then give him the following ini- 
tial test. 

You make him stand before a large wheel (the wheel 
placed at your disposal is of three feet diameter) with 
its axle in a horizontal position perpendicular to his 
line of regard. He looks at the circumference of the 
wheel and sees there large digits appearing from above 
and passing away below. You notice that only the digits 
1, 2, 3, 4, 5, 6, 8, 9 are used and that they appear at 
random, without any order whatsoever. The reason 
why and 7 are omitted is this. You.will later ask your 
partner to read the digits aloud as they appear, and 
to pronounce them very pointedly. This can be done 
only with monosyllabic words; and therefore the bisyl- 
labic digits are left out. 

Before the wheel you place a screen with a window 
so that most of the wheel is never visible, and that never 
more than two digits are simultaneously visible thru the 
window. 

Now you adjust the speed of the electric motor which 
drives the wheel. You increase the speed of the wheel 
while your partner is reading off each digit at the mo- 
ment when it disappears behind the bottom frame of the 
window. As soon as you have reached (be a little pa- 
tient in doing this!) such a speed that your partner be- 
gins to find it impossible to read off each digit correctly, 
you decrease the speed again a little. Thus yow have 



HABITS OF RHYTHM 31 

found the greatest speed at which your partner can read 
off these digits pointedly without making any errors. 

Now you are ready for the real test. Before your 
partner, between him and the wheel, you put a solid 
little table or wooden stand, just high enough for him, 
w^hile he is standing, to place his hand on conveniently. 
You then give him a short-handled and rather heavy 
rubber hammer to hold in his hand, and tell him to hit 
the table with the hammer on reading off every seventh 
digit without letting this hammer work in any way in- 
terfere with the manner or the correctness of reading 
off the digits. Seat yourself a little sidewise and to the 
rear where your partner can not see you or your' mo- 
tions distinctly. Count silently so that he can not hear 
you from 1 to 7, beginning with each one of his hammer 
strokes. In both your hands you hold little automatic 
registering machines, so-called tallying registers. When- 
ever he hits correctly after you have said to yourself 
"7", you press the button in your right hand. When- 
ever he makes an error, not hitting at the right moment 
or doing it at a wrong moment, you press the button in 
your left hand, and at the time of his hitting begin 
with ^'1" a new silent counting. 

Continue this test for five minutes. In order to do 
that conveniently, you start, at the moment when your 
partner begins his hammer and reading work, an inter- 
val timer set to ring after five minutes. 

During the test, while j^our chief attention must be 
paid to pressing correctly the buttons in your hands, 
you must give enough secondary attention to your part- 
ner's reading to lielp him to be aware of it if he should 
fcill into reading slovenlv, leavinu' out digits wliicli ac- 



32 PSYCHOLOGY DEMONSTRATIONS 

tually appear, or reading the digits wrongly. Disconnt 
a merely occasional lapse of speech such as — maybe — 
pronouncing sic instead of six or fro instead of four. 
But do not permit real and serious errors in reading, for 
your whole test is based on the presumption that your 
partner reads off the digits correctly. ''Errors" are 
permitted and valuable in this demonstration only in so 
far as the rubber hammer may strike at the wrong digit. 

At the end of the five minutes look at your tallying 
registers and record carefully the numbers they tell you 
for correct strokes and errors. Also ask your partner 
(and write down) whether he considers this hammer and 
reading work easy or difficult to perform correctly. You 
would better ask him this question hefore you have told 
him the numbers which you have found on your tally- 
ing registers. 

Your partner will now test you in the same manner, 
with this difference only, that he will tell you to hit tlie 
table with the hammer on reading off every fifth digit. 

These tests now will not be repeated for at least two 
months. Meanwhile you will both regularly five minutes 
(neither less nor more) per week take an exercise train- 
ing you in the rhythm habit which you have chosen. It 
is essential that this exercise be taken faithfully. Be- 
gin today. 

Your partner, training for the 7-stroke rhythm, will 
proceed as follows. He will stand before the frame de- 
scribed on page 347 of your text. He will take the rub- 
ber mallet in his right hand (we suppose him to be right- 
sided, — if his left side is his better side, all rights and 
lefts must be exchanged) and hit the button on the left. 
He carries out the rebound and makes a preparatory 



HABITS OF RHYTHM 33 

movement for doing the same thing toward the right 
button. 'After the next preparatory movement, for the 
left button, however, he ''changes his mind" by adding 
a further preparatory^ movement leading his hand thru 
a short curve (a quadrant) to a place a little above the 
center of the frame. This finishes the whole group of 
seven motions. There is no counting of any kind nec- 
essary in this performance, either by your partner or 
by you. 

After the horizontal performance your partner now 
does the same in the vertical direction. The final curve 
leaves his hand a little to the right of the center of the 
frame. He goes again thru the horizontal performance, 
again thru the vertical performance, and so on, until 
you tell him that his five minutes are over. Watch his 
motions while he exercises, and if he does not do the 
work right, correct him. You are responsible for his 
learning to do the w^ork right. See to it that he does 
not make any pauses between his motions, especially not 
after the quadrant, or extend or reduce the time for any 
of the seven motions so that it becomes very different 
from the duration of any of the other six. Each of the 
seven motions should with fair approximation be of the 
same duration. But no exactness of equality of the 
duration is desirable. Let him work naturally. By fair 
approximation to the same duration is meant only that 
none of the seven motions must ever last even approxi- 
mately tivice as long as any of the other six. 

After your partner has finished his five minute exer- 
cise, he makes you take your five minute exercise. You 
go thru the performance consisting of five group mo- 
tions, which is described on page 347 of your text. Botli 



34 PSYCHOLOGY DEMONSTRATIONS 

;y^ou and your partner take your five minute exercises 
re^ilarly once a week for at least two months. Then 
you are ready for the final test. 

In the final test you proceed as in the initial test. You 
put your partner before the wheel and make him read 
aloud the digits and hit the table with the hammer on 
reading off every seventh digit, for five minutes. 

Compare the numbers given by the tallying regis- 
ters in your hands with the numbers obtained in the 
initial test. The difference is an indicator of the strength 
of the rhythm habit which your partner may have ac- 
cjuired during the exercises of the last two months. Also 
ask your partner how easy or difficult he considers the 
combination of his hammer and reading work now. 

YIII. The Accommodation Reflex Used for a Purpose 
Other than Adjustmsnt of the Eye. 

Read what you find on pages 189 and 190 of your text 
on the reflex which flattens the lens, and on page -244 on 
the use of the accommodating apparatus for the pur- 
pose of "localizing in more or less depth" (by habit or 
by reflex). 

For this demonstration you use an apparatus designed 
by iHering (of whom you have heard in connection with 
color vision). It is essentially a box-like frame which 
has a small object (for example, a bead) suspended as 
a mark at about the middle distance from front to back. 
Your partner looks thru a horizontal slot steadily at this 
mark. The slot is so arranged (for example, by dupli- 
cating it, one behind the other) that your partner can 
see neither the floor nor the ceiling of the "box", but 
easily a little space above and below the mark. 



A REFLEX USED FOR A NEW PURPOSE 35 

You insist on your partner keeping one eye securely 
covered anci out of function. 

Now you give a '^ Ready" signal and two or three sec- 
onds later drop a bead or other object similar to the 
suspended one. There are four holes in the roof of the 
box, two in front, two in the rear of the mark, which 
you must use at random for dropping. These holes are 
arranged so that, no matter which of them you use, the 
object dropped will appear to your partner at about the 
same distance sidewise from the mark. You ask your 
partner whether it was farther or nearer from him than 
the mark. According to his answer you write in your 
note book, in a column, case after case, either F or N 
and add to it a cross if the answer was wrong, a ring 
if the answer was right. 

It is advisable to vary a little the size of the objects 
dropped. Why ? 

Never repeat a case on account of being told by yonr 
partner that he does not feel sure. Call his attention to 
the fact that you are not trying to find out how clever 
he is, and that he ought to have found out by this time 
that the errors recorded in psj^chology demonstrations 
are often the only really valuable part of the procedure. 

When you have twenty-five cases, stop. Take a rest 
by letting your partner work with you in the same man- 
ner. 

Then proceed again with your partner as you did at 
first, but with tliis difference that now you do not drop 
the object, but lower it slowly on a fine black thread, 
making sure that you go below the level of the mark and 
that 3'ou expose the object to your partner's eye (one 



36 PSYCHOLOGY DEMONSTRATIONS 

eye) between two and three seconds. Finally your part- 
ner does the same with you. 

Now compare the number of errors you got in drop- 
ping and in lowering. How do you explain the differ- 
ence ? 

After this both you and your partner make another 
series of twenty-five drops (remember "drops only") 
each, but this time with both eyes open. How many 
errors do you find now? Do you think that the facts 
found warrant the belief that another adjustment, men- 
tioned on page 244 and also on page 188 of your text, 
plays a role here ? Do not answer rashly ! 

If this adjustment (the angle of convergence) is fol- 
lowed by an action of ' ' localizing in more or less depth, ' ' 
what is the direct stimulus of this action of localizing 
in depth? Look to pages 148 and 149 of your text for 
a suggestion. 

Can the sensory-motor function hinted at in the last 
two paragraphs be the explanation of the facts which 
you observed in dropping things - before your partner 
while he had both eyes open ? If so, why so ? If not, 
why not? 

Could the habit of ''localizing in depth" described 
on page 258 be the explanation of the facts discovered 
by dropping things before your partner while he had 
both eyes open ? If so, why so ? If not, why not ? 

IX. A Species of Motor Condensation in the Nervous 
Functioning. 

First examine your partner and, if necessary, teach 
him all that is said on pages 220-222 of your text. You 
find it said there that "special conditions delay the re- 



MOTOR CONDENSATION 37 

action" to each of two reflex responses; and finally 
neither of them occurs, but instead of them the pro- 
nunciation of a certain word. This ' ' delaj^ ' ' might make 
YOU feel inclined to become shaky in your conviction 
that ''states of consciousness are not to be regarded as 
causes in science." A friend believing otherwise might 
urge you to admit that ''the delay is caused by your 
partner's thinkmg and that that thinking then becomes 
the real cause of his later pronouncing that w^ord. ' ' We 
shall help you here to defend your position. 

It is really only a figure of speech w^hen we say an 
action is delayed. A reaction cannot be delayed, for 

the nervous system is not (look up in 

the index of your text the items "afferent and efferent" 
and find in the text the words with which to fill in this 
blank), but a system of conductors. No stream of excita- 
tion can enter the system without a like stream passing 
out during the time. The ' ' delayed reaction ' ' only means, 
really, that you cannot notice any reaction of which you 
are sure that it belongs to that stimulation. This means 
that the muscular reaction is so widely scattered that 
it simply becomes a part of what the physiologists call 
"the general muscle tonus". 

' ' But why is it thus scattered ? Why does the nervous 
current, instead of going mainlj^ to the (reflex) motor 
point corresponding, go in the main to innumerable 
scattered motor points?", asks your friend. The answer 
is simple enough: Because some preoccupation (compare 
the pages from 91 to 97 of your text) has been estab- 
lished which opens up the patlis thus scattering the cur- 
rent. Such a preoccupation can easily be established, 
for example, in accordance with our speech habits, by 



38 PSYCHOLOGY DEMONSTRATIONS 

somebody saying' .authoritatively ''No, no,' — don^t, 
don 't ; " or by your instruction given previously to your 
partner to the effect that you care nothing about the 
direct localizing reflex movement. The current will then 
go, in the main, to the higher center serving the repro- 
duction of the words of instruction and thence to the 
muscle systems pronouncing these words or to the gen- 
eral muscular system, in the latter case merely adding 
imperceptibly to the general muscle tonus. 

• But these muscle contractions, belonging to the speech 
functions or to the general muscle tonus, are themselves 
of the nature of (kinesthetic) stimuli (compare what 
you find on pages 361 and 362 of your text) insuring 
a continuation of the streaming of excitation thru tl\'^ 
nervous system, again resulting in either the pronun- 
ciation of such words or an addition to the general mus- 
cle tonus. And this streaming of excitation more or 
less scattered thruout the nervous system may go on for 
seconds or minutes (or even hours) without bringing 
about any muscle action which you would regard as 
worthy of being called ''the" reaction to the initial 
stimulus. 

Gradually, however, a change may come about in the 
streaming within the nervous system. It may be that 
from the beginning the intensity of the flux was a trifle 
stronger in a certain motor direction than in all others. 
By the law of deflection, (compare pages 102 to 106 of 
your text) then, the flux in that direction must become 
stronger and stronger and very strong, if you only give 
it time enough. Or a second stimulus occurs and estab- 
lishes a current in a certain direction (by reflex or habit) 
which now gradually draws the other currents into it- 



MOTOR CONDENSATION 39 

self. Thus, finally, a definite action occurs which seems 
to have such a clear logical relation to the initial stim- 
ulus, that everybody calls it "its reaction", merely 
adding that ' ' it was delayed. ' ' 

The delayed reaction thus is in no way mysterious, 
for the simple reason that it is not in reality a delayed 
reaction. It is mysterious only to those who think of a 
nervous process as if it were like a ball ("one" ball, 
"the impulse") running along a bowling alley, perhaps 
striking the walls here and there and very soon reach- 
ing the ten-pins. But if there should be an elevated 
ridge made of inclined planes and crossing the alley, the 
ball may run up and stay on the ridge a long time in 
delicate equilibrium. A little later another ball may 
get lodged on the ridge, and another and another. But 
after a considerable time (delay) a naughty boy ("the 
will") who has no respect for the laws of "mere mat- 
ter" comes and kicks one of those balls against the 
others with the result that they all run off the inclined 
plane and toward the ten-pins. This antiquated con- 
ception of the brain as a tank (or, here, ridge) where, 
things (knowledge) may be stored for a long time until 
a mysterious force drains the tank, is still rather pop- 
ular. But modern biological thought is in the direc- 
tion of regarding the nervous system as what Ave called 
it, a system of conductors and nothing else. 

Returning now to what you want to demonstrate, you 
are going to touch your partner with two compass 
points, having previously instructed him to respond witli 
a single reaction, either that of saying "one" or that 
of saying "two". You are thus going to demonstrate 
that species of motor condensation of the nervous Uwc- 



40 PSYCHOLOGY DEMONSTRATIONS 

tioiiing which is the most common species of motor 
condensation, — so-called space perception. Ask your 
partner whether he understands clearly what your text 
means by sensory condensation and motor condensa- 
tion. Make it still clearer to him by referring to the 
figures and the descriptive words on pages 224 and 225. 

Then draw in your note book nine vertical lines, leav- 
ing between them eight blank columns. The first, third, 
fifth and seventh of these columns you fill in with the 
consecutive numbers from 1 to at least 20. You will 
soon find out how far you will have to go beyond 20. 
These numbers really stand for one-sixteenth, two-six- 
teenths, and so forth, of an inch. 

You now have the choice between two methods. You 
may proceed thru the column in regular order and first 
touch your partner with two compass points 1 sixteenth 
of an inch apart, then with two points of 2 units in- 
terval, then of 3 units interval, and so forth. But in 
that case you have to touch him now and then, very 
irregularly, with one point only; and if he should say 
/'two" even in such a case, you have to tell him that 
he has spoiled the whole procedure and that everything 
(the whole column) has to be done over again from 
the beginning, your record thus far obtained being 
destined for the waste basket. 

If you and your partner do not like that, you have 
to choose the second method, in which the distances 
written in the column are used in quite irregular or- 
der. But let us suppose you succeed in training your 
partner never to say 'Hwo" when there is the least 
doubt about there being two. You can then, use, and 
we assume now that you are going to use, the first 
method. 



MOTOR CONDENSATION 41 

You already know about the necessity of a ''Ready" 
signal before giving the stimulation. When applying 
the points, remember that you must not apply them in 
the manner in which a bird pecks at a grain. You must 
place the two points on the skin with equal pressure for 
ahoiot iivo seconds, certainly not less than 1^ seconds. 
You must place them firmly, so that you see the skin 
indented ; but not with so much pressure that your part- 
ner 's skin will show the marks even half a minute after 
removal of the points. Treat your partner as you would 
like to be treated yourself. 

Choose a region on the inner surface of your part- 
ner's arm near the wrist. Choose a smooth, fleshy re- 
gion, not one underlaid with tendons. During the first 
two series of applying the compass points apply them 
so that a line drawn thru them would be parallel to the 
axis of the arm. During the third and fourth series 
apply the points crosswise. 

During the first and third series pass from the smallest 
to greater intervals, during the second and fourth series 
from greater to smaller intei'vals. Do not stop the first 
series until you have had at least eight consecutive 
''two" judgments pronounced by your partner (eight 
not intermingled with "one" judgments). Write in 
the proper blank column to the right of each stimulus 
the judgment "one" or "two." 

You now notice — most probably — in each of these four 
columns a middle region in which appear both the judg- 
ments "one" and "two" mingled. Write at the bottom 
of each column that distance of tlie compass points 
which corresponds to the middle of this thvesliold re- 
gion. Then take the middle between those two locations 



42 PSYCHOLOGY DEMONSTRATIONS 

in the first two columns and also the middle between 
these two locations in the last two columns. These two 
values enable you to compare very quickly the threshold 
lengtliAvise with the threshold crosswise. Did you suc- 
ceed in demonstrating what your text says about this 
matter on pages 221 and^ 222? 

X. Calling Tilings Large. 

Place on the table before your partner a large sheet 
of paper and on it a little scrap of dark colored (per- 
haps green) paper, round, square, or of any irregular 
shape, and of about two inches diameter. Tell him to 
look steadily at one of the corners or at any other 
marked point of the paper scrap until you have counted 
2|00. It is important that he hold his eyes as still as 
possible during that period. Immediately after count- 
ing 200 you tell your partner to look steadily at a point 
on the floor and to say "I see it" as soon as he sees 
something of the same shape as the paper scrap appearing 
like a ghost on the floor. At once you make him look, 
for the same purpose, at a point on the nearest wall of 
the laboratory room ; and after that on the ceiling ; and 
after that on the farthest wall of the room. And then 
you may hold a uniformly colored book cover about six 
or eight inches before your partner's eyes and tell him 
to see the ''ghost" there. 

If the ''after-image" (this is the technical name for 
such a ghost; compare page 290 of your text) did not 
last long enough, give your partner a few minutes rest, 
and then repeat the whole procedure, trying to make 
him look at the several places in quicker succession, — 



CALLING THINGS LARGE 43 

maybe also after counting* a little more slowly and 
strengthening' the after-image by lengthening the time 
of exposure. 

Now ask him how big he would call the ghost seen on 
the book cover, the floor, the nearer wall, the ceiling, the 
farther wall. Tell him, if he talks of its color, that you 
care nothing about its color, but that you are interested 
solely in its varying size. 

Ask your partner whether he thinks that there is any 
reason for believing that the number of sensitive cells 
which are in a state of excitation has anything to do 
with calling a thing large or small or larger or smaller. 

No matter whether he answers this last question in 
the affirmative or in the negative, — ask hdm, further, if 
he thinks that the Other-One could be misled into calling 
a small thing* large or a large thing small by keeping 
from him the most, or the more, impressive information 
concerning the distance which the thing actually is from 
his forehead. 

For example, if you want to induce the Other-One to 
accept a dime in exchange for a dollar's worth of gro- 
ceries, would you be likely to succeed if you thrust your 
hand, holding the dime, forwurd toward his eyes until 
they are within a few inches of touching him? 

Qr if you want to induce the Other-One to talk of 
your brother, three hundred feet away, as ''being like 
an ant", would you be likely to succeed if you put 
your brotlier three hundred feet away on a busy street 
where there are plenty of people seen in the space he- 
tween? 

Or if you want to induce the Other-One lo talk of 
your brother, three liundred feet awav, as "lieinu- like 



44 PSYCHOLOGY DEMONSTRATIONS 

an ant", would you be more likely to succeed if you 
stand with him on. the roof of a sky-scraper, looking 
over the railing, having put your brother three hundred 
feet below on the street, witJi nothing visible in the space 
hetweenf 

If there were men everywhere floating in the air in 
the space between, there would be some impressive in- 
formation concerning your brother's distance. Do you 
think the Other-One would still talk of him as ''being 
like an ant"? 

Now let your partner formulate the rule by which 
''information" (right or wrong, but) impressive and 
believed about the distance, influences the Other-One in 
calling things large or small (quite independent of the 
excited area on the retina). 

Was there any reason for thinking that this informa- 
tion (right or wrong, but) impressive and believed about 
the distance, was impressive when your partner pro- 
jected the after-image on the book cover, the wall, and 
so forth? 

Now ask your partner how he would answer the follow- 
ing question: "What are the two factors on both of 
which the Other-One's habit of calling things large 
(larger, smaller, and so forth) depends, provided that 
both factors exist?" Tell him that both these factors 
are already hinted at in the preceding pages: one 
in the paragraph beginning with "Now let your", the 
other in the paragraph beginning with "Ask your part- 
ner". Which of these two factors constitutes a simpler 
and which a more complex habit? 

What relation has this demonstration to what is dis- 
cussed on page 224 of your text with reference to figure 



CALLING THINGS LARGE 45 

B? Apply that figure to each of the two factors just 
hinted at. 

What relation has this demonstration to what is dis- 
cussed on page 226 of your text in the paragraph be- 
ginning with ''Space"? 

What is the only difference between this demonstra- 
tion which you made on your partner and that experience 
with the Other-One which is described on the lower half 
of page 242 of your text? What is the only difference 
in the manner of stimulation described there and that 
used in this demonstration? (How long did you wait 
between seeing the moon at the horizon and at the 
zenith?) 

What is said on page 243 of your text about reversing 
the substitution of one action for another action ? How 
is this related to the figure on page 124 of your text ? 

Be sure to remember what you have learned in this 
demonstration in order to make use of it in demonstra- 
tion XI, and also in demonstration XIV where ''size" 
concerns us in connection with pseudoscopy. 

XI. Wasted Habits of Estimating Space. 

What is that name which is used in your text for both 
wasted reflexes and wasted habits? Use the index in 
order to give the answer. 

What does your text say about the Iiabit of o^■eresti- 
mating or underestimating angles? Look in the index 
under angles. 

If we call the habit of calling an angle by sucli a name 
as ''large" or "small" or "nearlj^ 90 degrees" a suh- 
stituted action, what does that action whidi is in this 



46 PSYCHOLOGY DEMONSTRATIONS 

case replaced by tliis substitute consist in? Does not 
the replaced action consist in calling the thing flat? 
Look at the thing on page 238. 

What do we mean when we call a thing (any of the 
things in the accompanying figure) ' ' viewed perspective- 
ly " ? " Per ' ' literally means ' ' thru ' ' ; and ' ' spect ' ' lit- 
erally means "seen." What has this meaning of ''per" 
to do with the preceding paragraph? 




Make in your note book carefully an enlarged draw- 
ing of any one of the things pictured in the figure here 
and tell your partner to ''look thru" that thing. If 
you have not yet agreed with your partner as to what 
is meant by the command to look "thru" a picture, 
return to the last paragraph and reach an agreement. 
Mark the end points of a properly chosen line in your 
drawing a and h and tell your partner to folloiv this line 
in looking "thru" the thing. 

If your partner possesses some perspicacity, he will at 
once ask you : ' ' Must I look at a first and at Z> later or 
at h first and at a later?" Choose one of these two 
points and tell your partner to arrest his eyes on it and 
not to continue looking thru the thing until you give 



WxVSTED HABITS OF ESTIMATING SPACE 4< 

your permission. Then count silently to 15 and sudden- 
h% instead of giving him permisssion now to look thru 
the thing, cover your drawing with a piece of paper. 
At once ask your partner to show you, using pencils or 
matches for this demonstration, how the line was (or, 
perhaps, the lines were) situated in the space thru 
which he had hoped to obtain your permission to look. 
Write down in your note book a description of the situa- 
tion of that pencil or that match (or, if two or more lines, 
those pencils or those matches) in some such manner 
as is indicated by this example, "Pencil going away 
from me into depth, slanting a little to the right and 
downward," using whenever necessary other terms, 
perhaps even opposite to those in this sample descrip- 
tion. 

Now repeat everything spoken of in the last para- 
graph, Avith this difference, however, that you now choose 
the other point as the one on which your partner has to 
arrest his eyes before being permitted (which he actually 
is not) to follow the line in looking "thru" the thing. 

You may have to repeat both cases many times before 
you derive the conclusion that a certain habit of naming 
(describing) prevails in the one case and another certain 
habit in the other. "While j^ou are investigating what is 
the prevailing habit in each case, you really make a 
statisiic((l investigation in the one case and in the other 
case. A single observation is insufficient because habit 
functions (especially hnman habit functions) are very 
much subject to accidental influences (unknown and 
uncontrollable by you). 

Now you will have to answer two (piestions wliich 
will i]iform you wlietlier you have really pi-otited from 



48 PSYCHOLOGY DEMONSTRATIONS 

this demonstration and from your study of the text or 
not as yet. These two critical questions are here directly 
following. 

If you should hear anybody call one of your two cases 
a "perception" and the other case an '' illusion", how 
could you defend him and justify his talk? 

If you should hear anybody call both of your cases 
''illusions", how could you defend him and justify his 
talk? 

If you have told your instructor what your answers 
are and feel quite sure now wdiat it is what your text 
calls an illusion, proceed with your partner in an en- 
tirely novel way. Tell your partner to arrest his eyes 
as long as he wants to on that end point of the line 
which you have chosen for the start, then to follow the 
line and to arrest his eyes on the other point again as 
long as he wants to. Let him demonstrate now" with 
pencils the location of the lines. Does this case agree 
with the first above? Or with the second above? Or 
is it different from both? Perhaps a kind of combina- 
tion of both? Combined in what manner? Are both 
points nearer than each other or does time play any role 
in the judgment? 

Try then still another procedure. Tell your partner 
to proceed from the starting point and to follow the line 
in looking thru that thing, but to be sure not to arrest 
his eyes even for the slightest moment at the point which 
you have not chosen for the start. Tell him to be sure to 
slide over the end point into any direction of space. 
Ask him to demonstrate how the line is then situated in 
space. Does this case agree with the first ? Or with the 
second? Or is it different from both? Whatever it may 



WASTED HABITS OF ESTIMATING SPACE 49 

be, why is it so'^ That is, in the formation (long ago) 
of this habit, Avhat action was substituted for what? 

Whiat general statement Avould yon make, then, con- 
cerning the question : What is the nature of the class 
of stimulation which in these demonstrations called forth 
either the response of saying "This point is the nearer 
one of the two" or instead of this response the equivalent 
response of demonstrating with the aid of a pencil the 
situation in space of a line contained in the picture? 
''T/?e point not favored hy the adjustment of the eye is 
generally called nearer'' — would that statement he the 
answer? 

You have thus far workect with only one of many 
drawings any one of which you could have used for the 
same demonstration and of which you see only seven 
representatives in your figure. Make in your note book 
now an enlarged drawing of each of the other six and 
demonstrate your partner's habits on each one of them 
in the same manner of procedure just used. Tell in 
A^our report Avhy the habits illustrated by all these seven 
drawings are often — and justly — called (1) illusions of 
(2) reversible (3) perspective. 

After having used all the pictures of the last figure, 
now show your partner the next figure, which looks like 
two solar systems. Ask him the following question: 
' ' If you were asked to cut out with a pair of scissors the 
centers of the two solar systems pictured here (that is, 
the two suns) in order to use these two suns as pictures 
for the decoration of the walls of your room, and if you 
had been asked to match tliese two pictures of only the 
central suns as well as possible, which of the two con- 



50 



PSYCHOLOGY DEMONSTRATIONS 



centric circles seen in the right system would you prefer 
as a match for that cut out from the left system?" 

Your partner's answer is undoubtedly the result either 
of his reflexes or of his habits. Was his answer deter- 
mined by the first or the second or both of these two 
habits enumerated below? 



o o 
o o 




(1) Substituting for the phrase 'Hhis is small and 
that 'is, still smaller" the new phrase ^'that thing might 
be too small to be a match." Do you think he has this 
habit ? You might find out by skilful questioning wheth- 
er such substitutions exist in his nervous system. Try 
to find out. Skilful questioning for the purpose of dis- 
covering what a person's hidden habits are, is nowa- 
days, by many who use it professionally, called tech- 
nically " psychanalysis. " You can psychanalyze your 
partner, if you just try hard enough. The fact that 
many of your partner's habits are hidden from you 
(maybe hidden from him, too), does not indicate that 
they are weak habits. However, you may perhaps feel 



WASTED HABITS OF ESTIMATING SPACE 



51 



confident as to whether he has this habit or not, without 
even psychanalyzing him. 

(2) Substituting for the nomenclature ''large system 
— small system" the nomenclature ''near system — far 
system" (comptare in your text on page 241 what is 
said of figure A) and then again substituting for this 
latter reaction the pronunciation of "small and large 
sun." Has this last habit been discussed or hinted at 
in any previous demonstration in this manual? Do you 
think your partner has this habit? 

What then is your final answer to the question : Was 
your partner's choice determined by the habit (1) or 
by the habit (2) or by both? 

In the case (2) just referred to, was there again 
"perspective"? If so, answer the question : What thing 
was here the start and what thing was the end of the 
movement of looking thru? 

Now turn to the third of the figures of this demon- 
stration and show your partner the three pictures of 
which it consists. In one of them he sees on one side a 





















^^ — ^ 




1 1 t 1 M 1 1 1 1 M 1 1 1 1 1 1 





















figure wliich looks like the cross-section of an old- 
fasliioned ii-on kettle, on the other side somethina' re- 



52 PSYCHOLOGY DEMONSTRATIONS 

sembling a palisade. Ask your partner whether he 
thinks that after cutting out with a pair of scissors the 
exact kettle he could or could not cover the palisade. 
Would a piece of the latter picture remain uncovered 
by the kettle? Or, if he tried to cover the kettle, would 
a piece of it remain uncovered by the picture of the 
palisade ? 

Ask him the same questions with respect to the pic- 
ture of which one side looks somewhat like the cross- 
section of a thick cushion and the other side like steps 
leading up to a building*. 

Ask him again the same questions with respect, to 
the third picture of the figure, where you have on both 
sides something looking like a fence and between the 
two fences a piece of unfenced ''landscape." Ask him 
in this case whether he thinks that by cutting out the 
horizontal strip of one of the fence pictures he could or 
could not exactly cover, or would cover more than, that 
strip between them picturing a ''vacant landscape." 

Has "perspective" anything to do with these "wasted 
reactions"? (By the way, what reactions of your part- 
ner are here wasted?) Does your partner look "thru" 
that cushion? Does your partner look "thru" that 
flight of stairs? Does your partner look "thru" that 
kettle? Does he look "thru" that palisade? Does he 
look "thru" that piece of fence? Does he look "thru" 
that vacant landscape ? In every case in which he really 
looks "thru" something definite, be must tell you what 
the start and the goal were between which the "thru" 
movement occurred. Perhaps there was less looking 
"thru" in some of these pictured things than in others. 
Does that make your partner's illusions plausible? 



WASTED HABITS OF ESTIMATING SPACE 53 

(Remember that looking- "thru" means favoritism to 
some point in a certai?! eye-adjustment. Compare p. 49.) 

A very different way of explaining these illusions is 
the old-fashioned one of some who have said that the 
six kinds of things shown in the last figure should be 
put in two classes: (1) Areas w^hich show subdivisions 
and (2) areas which show no subdivisions. They have 
further said that it is worth while to remember the 
"law" that a subdivided area always looks longer than 
one that is not subdivided. 

Let us warn you against that "law". It is not worthy 
of such a name. Trying to appl.y that specious law you 
might ask your tailor to subdivide your suit lengthwise 
by designing it with mau}^ lines running across it, liori- 
zontally, as in that flight of stairs. If you hoped that 
that would make you appear taller to other people, you 
would be disappointed. Why? Because the length of 
your body does not offer to the spectator any "perspec- 
tive," and nothing depending on "perspective" could 
thus become actual in the habit functions of your friends 
looking you over. 

On the contrary, your friends, instead of calling you 
tall, might call you stout because the horizontal lines 
would be likely to induce them to give your width that 
very measurement which you are not anxious to have 
applied to you, which indeed you are avoiding. As in 
vesture so in architecture subdivisions made by long 
lines do not call forth any exaggerated judgments of 
the space crosswise to these lines, but rather of the space 
along tlie lines. In Gotliic arcliitecture, for example, the 
prevalence of the vertical lines is intended to — and does 
— impress the sj)e('tat()]' with tlix* (lircctioii le.-uling to 



54 PSYCHOLOGY DEMONSTRATIONS 

, heaven. And in classic architecture the long horizontal 
lines tend to cair forth the judgment of ''broad" and 
firmly resting on the earth rather than that of ''tall". 
Beware, therefore, of applications of this specious law 
to dressmaking or to architecture. 

Xll. Natural and Artificial Blind-Spots. 

Anatomy tells you that the spot on the nasal side of 
your partner's retina where the optical nerve enters 
is not supplied with sensory cells. Use the index of 
your text and find out what your text tells j^ou about 
the possibility of reacting by means of the localizing re- 
flex to a stimulating object which sends its light rays 
exactly to that spot. 

How Avould you proceed in order to demonstrate the 
blind spot in your partner's eye? You might take an 
old newspaper and paste somewhere on the printed mat- 
ter a round bit of white paper of about one inch di- 
ameter. Then make a conspicuous fixation mark (a 
cross made with a black or colored pencil, for example) 
about five inches to one side of that piece of white 
paper. You may ask the instructor for some cards 
already prepared in the manner just mentioned. 

Are you going to permit your partner to keep both 
eyes open? If not, why not? If you are going to use 
his right eye on the fixation mark, should the white 
paper be pasted on the right or on the left side from 
the fixation mark ? In order to answer the last question 
correctly, recall that the optic nerve does not enter the 
ej^eball in its ''pole" (where the fovea of the retina is 
located), but a little toward the nose in either eve. 



NATURAL AND ARTIFICIAL BLIND-SPOTS Oe) 

Now make j^our partner keep his eye steadily on the 
fixation mark while he moves that newspaper or pre- 
pared card toward and away from his face until he has 
found the distance at which he can truthfully exclaim 
that the white paper pasted on the figured background 
has entirely disappeared. From that moment on he 
must keep eye and newspaper or card perfectly still in 
order to answer your question w^hether he is willing to 
say that instead of the white paper there is now a hole 
in the figured background or what else he is willing to 
call it. Most likely what he now tells you about that 
spot itself will in no way differ from what he tells you 
about the surroundings of the spot. Try a checker 
board and other figures on your partner for the same 
purpose. 

There are, however, exceptions to what was said at 
the end of the last paragraph. Por example, if you use 
two circles slightly overlapping, and have just the over- 
lapping parts extinguished by the blind-spot, it is doubt- 
ful whether j^our partner will describe the whole thing 
as two complete circles. Try him out. If he, on request 
to indicate what there is before him, draws two incom- 
plete circles, there is only one explanation of this. It 
must be a stronger habit. He must be more familiar 
with things resembling two incomplete circles than witli 
''two rings slightly overlapping". Try to psyclMualyze 
him and thus to discover Avhat his liidden habits are. 
Try to find out whether he handles this or that oi- an- 
other kind of things more frequently. Suggest to him. 
in addition to pairs of things, such tilings as link sau- 
sages, bales of cotton or hay, j)arcels or sacks stuffed 
Avith soft material and tied tiu'litlv with a strinu'. nnd 



Ob PSYCHOLOGY DEMONSTRATIONS 

SO forth. Maybe you will discover why this case with 
the blind-spot was seemingly an exceptional one and 
after all is not exceptional. 

Now you can try out your partner's habits of using, 
instead of his natural, an artificial blind-spot. An ar- 
tificial blind-spot can easily be produced; it does not 
require any drug application or surgical operation. Just 
tell your partner to hold one of his fingers horizontally 
before one of his eyes about six inches from his face, 
while he closes the other eye. Make him look thru the 
window at the sky ; or make him look at a large ground 
glass window pane. After a little while ask him if his 
■finger is not beginning to appear as if it wanted to 
become transparent. But be sure to Avarn him against 
becoming too interested in his finger ; he must be much 
more interested in the sky or the ground glass than in 
that finger. If he answers your last question in the 
affirmative, tell him to hold a pencil at almost arm's 
length so that it crosses the finger and ask him if he 
can see the pencil thru the finger. You will get a very 
surprizing answer. However, if you think it over, you 
will recognize that the finger created ''an artificial 
blind-spot". And your partner's answer was depend- 
ent on his habits. Give an example of such a habit 
chosen from those which you observed with the natural 
blind-spot. 

However, without knowing what you were doing, you 
have actually done something to your partner that you 
should never do in psychology demonstrations. You 
have played a trick on him. You did it in the follow- 
ing manner. 

When you told your partner to close one eye, he 



NATURAL AND ARTIFICIAL BLIND-SPOTS .) / 

probably closed the lid with his lid muscles. Now, it 
is virtually impossible thus to close one eye entirely 
without closing the other eye at least partially. In all 
probability your partner closed the upper lid of the 
open eye so much that it obstructed considerably the 
pupil, that is, the optical opening of the eyeball. And 
even the lower lid probably obstructed the pupil. This 
obstruction has an optical effect which physicists 
call ''dispersion" of the light. For simplicity's sake 
let us in the following speak of black (which is really 
lack of light) as if it were a special kind of light. In 
all the reasoning that concerns us here it amounts to 
the smiie. 

Since the dispersion occurs mainly on the edge of 
the upper lid, much light is throAvn from the bright 
background above over the dark finger region. And 
some (more or less) light is also thrown from the bright 
background below over the dark finger region. Ask 
3^our partner if he does not observe that quite clearly 
as soon as he brings his eyelids a little more closely 
together. But when he holds his pencil vertically (cross- 
ing the Jiorizontal finger) behind the finger, instead of 
light *'the black", a dark streak, from the upper piece 
and the lower piece of the pencil is now thrown across 
the broken space between the two pencil parts. And it 
■is then, no matter what your partner's habits, unavoid- 
able that he should tell you that he sees the dark pencil 
unbroken ''thru" the much lighter, translucent, so to 
speak, fiiiger region. lie simply sees there the disper- 
sion of the black appearing pencil. 

You can make the existence of the fact just mentioned 
— this ti'ick played on your partner — still more obvious 



58 PSYCHOLOGY DEMONSTRATIONS 

by asking: him to slant the pencil 20 or 30 degrees. At 
once your partner will tell you that that pencil piece 
which is seen ''thru" the finger has broken into two 
parts, both being, not slanting, as the pencil, but ver- 
tical, the upper one fwlling from the place where the 
upper pencil touches the finger region, the lower one 
rising from the place where the lower pencil touches the 
finger region. And the falling one of these two vertical 
streaks is probably more conspicuous because the dis- 
persion of the black appearing pencil is probably more 
powerful on the edge of the upper, more obstructing, 
lid than on the edge of the lower lid. 

In order to avoid this trick you have to insist that 
your partner keep his seeing eye icide open, the lids as 
widely separated as possible. Obstruct, then, the not 
seeing eye, whose lids will also be widely separated, by 
tying a thick black cloth loosely over it. Now let him 
put his finger again before the seeing eye, against the 
same bright background. Let him hold his finger in 
any position, perhaps, for a change, in a vertical posi- 
tion. Let him look steadily until, again, the finger 
begins to become translucent, as it were. This will 
not occur so readily when you do not use that trick, and 
3"0u must have more j)atience with your partner now 
than before. But when it occurs, let him again place 
his pencil across at the same distance behind the finger, 
move it slowly up and down, change the angle of slant, 
remove the pencil altogether, replace it again, and so 
forth, but holding his finger and his eye as still as pos- 
sible during all this time. 

Notice if your partner's actions, describing what lie 
sees, do not reveal habits quite similar to those whicli 



NATURAL AND ARTIFICIAL BLIND-SPOT^ 59 

fiinetion with the blind-spot. If that is so, you are 
entitled to speak of an artificially created blind-spot in 
this case. 

Try now still another method. Take a red disk of 
about three inches diameter, put it on a Avhite disk of 
about five inches diameter, (the actual dimensions mat- 
ter little) and spin the set on the color wheel. Tell 
your partner to look at the color wheel steadily, best 
keeping his eye fixed on the center. After a minute or 
more ask him if the whole disk does not look as if a 
veil, partly more, partly less dense, had been dra^^^l 
over it: and if the white ring, more particularly, does 
not appear as if it were a translucent veil thru which 
a colored background could be noticed. Without spin- 
ning the double disk he would probably deny it because 
his liabits are not such that he would very readily apply 
to a white paper disk like the one employed the name of 
a veil, cloud, or something similarly translucent, while 
the disk was standing still and this or that dot, dent, 
or other special feature of it could be clearly noticed. 
But when the disk is spinning you may find him willing 
to do that. 

Ask your partner of what color the background is 
which seems- to shine thru the "veil". How do you 
explain liis answer? What must be his habits? How 
is this case related to the preceding two cases ? That is, 
if you speak, here too, of an artificially created ''blind- 
spot", what is the shape of this artificial blind-spot in 
comparison with the shape of the other blind-spots? 

Popular language in all these cases of blind-spots 
would say that the blind-spot ''is filled in by the imagi- 
nation". Compare, by utilizing the index, Avliat you 



60 PSYCHOLOGY DEMONSTRATIONS 

find about imagination in your text. More exact- 
scientific — language says in the case of a blind-spot 
merely that when your partner's action was observed 
by you, "not everything" which seemed to be reacted 
to, ''really existed" or ''need really have existed" as a 
stimulus. Thus you may say that you have here ex- 
amples of actions more complex than the stimulation 
seemed to ivurrant. Has this last statement any logical 
relation to the explanation of Aristotle's illusion given 
on page 227 of your text ? Does the case of reacting to 
a blind-spot perhaps require for its complete explana- 
tion the application of both the prniciples of figure A 
and figure B on page 224 of your text ? - , 

XIII. Binocular Rivalry and Co-operaiion. 

Read pages 245 to 255 of your text. Ask the instruc- 
tor to give you a collection of cards suitable to test your 
partner's actions in case a different picture is presented 
to a corresponding region of his right and his left eye. 
The question in these cases is not simply ' ' One or two ? ' ' 
It is to be taken for granted that your partner will 
always answer "One". Ask the instructor for a stereo- 
scope, so that you may easily present the picture on the 
right side to your partner's right eye and the picture 
on the left side of each card to your partner's left eye 
in such a manner that he will always look at the center 
of each picture and will always be inclined to say ' ' One ' ', 
in so far as this can be controlled by merely regulating 
the direction from which either stimulation proceeds 
toward the eye. 

But how can he, the organism, call out "One" when 
one of the two organs in service at the time orders him, 



BINOCULAR RIVALRY AND CO-OPERATION 61 

the organism, to call ''the thing" by one name and tlie 
other organ orders the same organism to call "it" l)y a 
contradictory name? You will notice that the organism 
escapes from this dilemma in one of three ways. Some- 
times by the two organs (1) compromising and thus in a 
way co-operating. Sometimes by the two organs (2) 
dividing the lahor, avoiding mutually an encroachment 
upon each other's division of the task, and thus in a 
manner co-operating. But sometimes the organs com- 
pete so fiercely that nothing is left to the organism to 
do l)ut to cany out (3) either all the time only the order 
of the one or only of the other, or to carry out alternately 
the order of the one for a little while only, then that of 
the other for a little while onlj^, again of the one, again 
of the other, and so forth. There is, of course, nothing 
absolutely contradictory in such an alternation. Do 
we not, free from contradiction, call, for example, the 
same field on a farm on alternate occasions a wheat field, 
a stubble field, a wheat field again, a stubble field again, 
and so forth ? 

In your partner 's reactions to the cards of which your 
instructor gave you a set find examples (1) of the first 
kind of nominal co-operation above mentioned of the 
sense organs, (2) of the second kind of nominal co- 
operation of the sense organs, and (3) of the obvious 
competition of the sense organs. Of course, true co- 
operation betAveen the two sense organs is such an or- 
dinary fact in human life that you would not liave to 
spend time in the laboratory in order to demonstrate it. 
Find these examples by showing to your partner the 
cards in the order mentioned here below. 

Begin with tlie card wliich is pink on one side and 



62 PSYCHOLOGY DEMONSTRATIONS 

light green on the other. Place it in the stereoscope 
and let your partner adjust the stereoscope to suit him- 
self. Give him ample time to look. Ask him if he ever 
calls the whole thing or any whole and uniform part of 
the thing ^'a, pinkish green or a greenish pink". Ask 
him if he ever happens to be inclined to say that a veil 
is being thrown over the thing or that colored clouds 
appear on it. Ask him again and again how he would 
describe it now, and how he would describe it now, and 
how now, and how now. 

Now be sure to read to your partner page 99, be- 
ginning with the last paragraph, and all of page 100 of 
your text. Then discuss with your partner whether his 
actions are more likely to be due to the law of the re- 
sultant or to the law of the competition of nervous 
currents. Was there anything in your partner's action 
that could be called a compromise ? Was there anything 
in your partner 's action that could be called a consistent 
and fruitful division of labor between the two sense or- 
gans? Was there anything that could be called fierce 
and never really ending competition? Which of the 
three ways of escaping from the dilemma (look three 
paragraphs back) is illustrated by this card? 

In the same way now try on your partner the card 
of which one side is dark yellow and the other side blue. 
Ask and discuss the same questions. 

Try now card 25 of ''Titchener's Series". Is there 
anything in your partner's action which you would call 
fierce and never really ending competition ? Or is there 
evidence that at least one of the eyes divides the labor 
so that it (I) leaves a certain task wholly to the other 
eye and (II) truly co-operates with the other eye in 



BINOCULAR RIVALRY AND CO-OPERATlOX 6-3 

everytliin^' else? Wliieli of these two cases, I and II, 
would then be represented by tvhich of the three figures 
on x)aiie 224 of your text ? And which of the two cases, 
I and 11. would be represented by the figure on page 105 
of your text? 

Try now card 26 of "Titchener's Series" on your 
partner. Is this case like that of card 25? Or almost 
like it? Or entirely different from it? If entirely 
different, what is the difference ? If almost like it, what 
is the only difference ? 

Try card 27 of the same series. Answer the same 
questions. What are the best conventional (that is, 
agreeing ^\'ithi universal customs and not only with your 
partner's individual language customs) names which 
the two-eyed organism could pronounce for the whole 
thing regarded as something real, in the several cases 
of the cards 25, 26, and 27? Would ''monogram" be a 
good name in one or more of the three cases? 

Next try on your partner the card which is an en- 
largement of the figure on page 253 of your text. It is 
number 28 in "Titchener's Series". Read what you 
find on page 253 and 254. Do you find with this card 
any true co-operation between the two sense organs? 
Do you find any competition that is of the kind of 
nominal co-operation which may be called division of 
labor? Do you find any nominal co-operation of the 
nature of a compromise? What conventional name for 
the thing (or that part of the thing which is in question) 
does your partner propose in case you Imve an affii-mative 
answer to the last of the preceding questions? What is 
gloss (or luster) ? What adjective with three liyphens 
is used on page 254 of your text instead of ''glossv"? 



6-i PSYCHOLOGY DEMONSTRATIONS 

Would there be gloss in this Avoiid if "time'' did not 
exist ? "What becomes of gloss when you photograph it ? 
Did you ever see a photograph of the gloss of a person's 
spectacles? Do you still call it gloss in the photograph? 

Tiy cards 29, 30 and 31. Does co-operation seem to 
weaken and competition seem to become fiercer as your 
partner passes from card to card? What must be the 
conditions of the streaming of excitation thru tlie nerv- 
ous system which make deflection as described on page 
105 of your text so rare a possibility with card 27 as 
compared with its probability in cards 29, 30, and es- 
pecially 31? Can previous habit formation (resistance 
reduction as in the figure on page 124 of your text) 
have anything to do with th^ese conditions? 

Now give your partner card 32 to look at. Tell him 
that the apparent and maybe surprizing "solidit.y" of 
the crystal is at the present moment a mere by-product 
which he maj^ overlook since he will have a chance later 
in the course to demonstrate similar solidities on you, 
as you will then on him. Ask your partner which of 
the questions answered in the affirmative when he looked 
at card 28 have an application here, both with regard 
to the crystal and with regard to the background. 

Give your partner cards 33 and 34 to look at and — as 
some people say — "psychanalyze" him, that is, listen to 
him carefully while he is talking himself out. Is there 
anj^thing in his actions while looking at card 33 which 
you would call a demonstration of true co-operation of 
his two sense organs? Is there at times a nominal co- 
operation of the kind of a compromise? Is there at 
times one of the kind of division of labor ? Is there at 
times any fierce competition resulting in the organism 



BINOCl^LAR RIVALRY AND CO-OPERATION 6^) 

alternately obeying the orders of the one only and tlien 
only of the other sense organ? If you answer ain^ of 
tlijese questions in the affirmative, write down exactly 
what part of the field of vision your answer refers to. 
AnsM^er the same questions with respect to card 34. 

Now use card 35 on j^our partner. We shall use this 
opportunity for discovering whether you are a good psy- 
chanalyst, that is, whether you have skill in guessing 
your partner's hidden habits about whose formation you 
have no testimony of witnesses. Does your partner's 
action make it probable that sometime in his life he 
acquired the habit of calling a real thing of a certain 
descriptio7i by a certain namei Of what objective de- 
scription, used by witnesses in court, say? Perhaps: 
being oval, with four legs, being blue, and now and 
then turning red? Or what other description? And 
by what name? Perhaps: a coffin? Or a rabbit? Or 
what other name ? As soon as you guess what the hidden 
habit is, his prevailing reaction to card 35 will become 
c|uite plausible to 3^ou. When you have found the right 
■name, pick out from our discussion of card 28 the ad- 
jective which is virtually, in some situation of life, tlie 
synonym of that noun. (Did your partner ever stand 
on the outside of a house looking at its parts?) 

Now give your partner card 36. Do your partner's 
actions reveal m\y true co-operation of his two sense 
organs?, and where in the fiekl of vision? Or any di- 
vision of labor?, and where in the field of vision? 

Card 37 will remind you of card 32 in this respect, 
tliat you may again l)elieve it to he intended for tlie 
demonstration of an apparent "solidity". However, 
Avhile the card miglit l)e used for that, that is bv no 



66 PSYCHOLOGY DEMONSTRATIONS 

means the intention here. Ask your partner if he dis- 
covers any gloss, any luster. If he does, discover the 
objective cause of it. You can discover that, if you 
utilize what you learned on card 28. What you had 
there in a big bulk, you have here in many little details. 
But it requires a very minute inspection and com- 
parison, a regular survey of the two pictures on card 
37 in order to discover a few of these details. You will 
not find them either in the boat or in the shrubs on 
shore. But where most likely? (Where in the land- 
scape would you expect gloss?) 

Take now card 40, which is described on page 255 
of your text. Read that page. Remember how your 
partner acted with the first two cards, when you put 
red before one of his eyes and green before the other, 
or when you put blue before one and yellow before the 
other. Do you conclude from your partner's actions 
that the competition between the nervous currents com- 
ing from the two eyes is equally fierce now when you 
put blue before the one eye and green before the other, 
or blue before the one eye and red before the other ? Or 
is there a greater tendency toward a nominal co-operation 
in the two cases of card 40 ? 

Would you accept the following threefold statement 
about the behavior of the nervous currents toward each 
other as an interpretation of your partner's actions? 

With antagonistic colors: — competition most fierce. 

With dissimilar colors : — competition much less fierce. 

With somewhat similar colors: — competition still less. 

Look up on page 283 of your text, in the lower para- 
graph, what colors are antagonistic. Do not fail to 
compare the figure mentioned there. 



BINOCITLAR RIVALRY AND CO-OPERATION 67 

Look up Oil page 270, in the paragraph beginning on 
that page and ending on the next, what is meant by 
colors being ''somewhat similar". 

Now give your partner card 38, wliich is really only 
a double frame. By placing in the two windows of the 
frame bits of colored or uncolored and brighter or dark- 
er paper, you can try out any combination of excita- 
tions of the two eyes that you may be interested in. 

Card 39 you can probably use most advantageously 
by instructing your partner to adjust the stereoscope 
so that the two inner (one blue, one red) squares co- 
incide within what he will call "the real thing"; and 
that the two outer squares (one blue, one red) remain 
separate and upon the outskirts of that thing. Give your 
partner ample time to watch, and listen patiently to his 
description. What former experiences are here ex- 
hibited again ? 

Card 41 may call forth in your partner the applica- 
tion of the name "green" to a certain part of the field 
of vision, and you may have ready at once, as ' ' explana- 
tion", the fact that painters often mix green paint out 
of blue and j'-ellow pigments. Disillusion yourself. You 
will learn on page 273 of your text that the explanation 
is not so simple. Cut two holes in a white piece of paper, 
and cover thus all the red parts of the card, and let your 
partner look again. You will discover, unless your pa- 
per is translucent, that the red is the chief if not the 
only cause of the "green" being spoken of by your 
partner. 

Card 42 will again exhibit some former experiences in 
a new variation. 



68 PSYCHOLOGY DEMONSTRATIONS 

Xiy. Stereoscopy and Pseudoscopy. 
Stereoscopy 

Take a hollow truncated cone, made of paper or tin, 
and place it before your partner so that he can see the 
outside (that is, with the smaller of the two circular 
opening's nearer to him than the larger opening). It 
is not necessary that the axis of the cone fall in the 
median plane. Indeed it is preferable to have the axis 
cross your partner's median plane under a small angle, 
say, one of ten deg'rees. See that your partner keeps his 
head as still as possible, while you make him close the 
left eye and draw with the pencil the two circles as they 
appear to his right eye in relative position, and then 
close this eye and, without having made any head move- 
ment, draw the two circles on the left of the drawing 
just made as they now appear to his left eye. Call this 
double picture for convenience's sake I. 

Then turn the truncated cone around so that your 
partner can see its inside and make him draw again a 
double pictare under the same conditions as before. Call 
this double picture II. Now ask the instructor to give 
you the cards of "Titchener's Series" from 1 to 24. 
Pick out from this series card 7 and see whether this 
agrees in its essential features with your partner's draw- 
ing I or with his drawing II. You can thus tell whether 
the person who drew the card 7 had the smaller opening 
of the hollow cone closer to himself or farther away from 
himself than he had the larger opening of the cone. 

Now read what you find about stereoscopic vision on 
pages 256 to 260 of your text. Memorize the two rules 
which you find on page 258 in the lower paragraph be- 



STEREOSCOPY 69 

ginniiifT with the word "Experience" and in the para- 
«iTaph beginning below this and ending on page 259. 
Without knowing these two rules by heart your chance 
of understanding stereoscopy and pseudoscopy is prac- 
tically zero. 

NoAv let 3^our partner place card 7 in the stereoscope 
which you get from your instructor. Let your partner 
properly adjust the instrument. Notice if he more fre- 
quently (if he speaks of '/nearer" and ''farther" at 
all) calls the smaller circle nearer or the larger circle 
nearer. (Of course, th^ere is no law of nature nor any 
statute law which could prevent him from doing either.) 
Is the greater frequency of one kiyid among his reactions 
in accordance with the supposedly existing habit which 
you just memorized in those two rules ? Or is it not in 
accordance ? 

Try now the cards 6 and 5 on your partner in the 
'same manner. "What is the likeness and what the only 
difference from number 7 of each of these cards? 

Try now cards 4, 3, 2 and 1. Apph^ again the rules 
whiich you memorized. Then let your partner use these 
cards in the stereoscope. If you should find him less 
determined in these (simpler) cases, can you state a 
reason for that? Are the orders, so to speak, received 
by the organism to do something definite with the things 
shown on these four cards fewer than they are with 
the cards 5, 6 and 7, and do you regard this as a plausible 
reason why the organism does this definite thing with 
more vacillation ? Do you ' ' stick up your hands ' ' with 
less vacillation when one highwayman ordei*s you to do 
it or when several highwaymen give you the order? 

Cards 8 and 9 do not introdiico any m^w in'inciple. 



70 PSYCHOLOGY DEMONSTRATIONS 

In card 8 there are two quite independent things to be 
seen at the same time. And in card 9 there are even five 
things, all independent, to be seen at the same time. All 
one can say is that these cards approach more the con- 
ditions of everyday life where, in seeing a furnished 
room or a landscape, one sees many things at the same 
moment. 

About the same is to be said of cards 10, 11, 12, 13 
and 14. The number of details seen at the same moment 
increases from case to case. 

Now take the photograph, card 15. Try to apply the 
rules (which you memorized) by proceeding in your 
reasoning in the opposite manner. Instead of picking 
out two things or details which are quite obviously, one 
picture in comparison Avith the other picture, displaced 
relative to each other, pick out two things (without us- 
ing the stereoscope at all) which are quite obviously at 
different distances from the pJwtographer. Then meas- 
ure their distance horizontally from each other in each 
picture. 

With most things you select you will need a pair of 
compasses, calipers, or a ruler to take that measurement. 
But with a few wisely selected things you can measure 
exactly enough with the naked eye, Avithout any cali- 
pers. To do that you must select two things which are 
almost exactly in line from the photographer, for ex- 
ample, the man and a point on the rail of the bridge just 
barely not hidden by his body. 

Card 16 is a very interesting pair of pictures of the 
moon photographed from tw^o laterally distant places 
on earth ; but you will find it almost impossible to select 
two things on its surface for the same comparison which 



STEREOSCOPY 71 

YOU just made iu the bridge pictures The photograph 
17, ou the other hand, is again very suitable for sueli a 
comparison of two things mth regard to their relative 
displacement in the two pictures. 

Cards 18, 19, 20 and 20-Extra will give food for re- 
flection to those students who are fond of it. But they 
Avill not elicit from joiir partner any very definite re- 
action when he looks at them in the stereoscope. 

Cards 21 and 24 serve the negative purpose of calling 
attention to the fact that only lateral displacement of 
one thing relative to another (no vertical displacement) 
plays a role in stereoscopy. If you were the Creator and 
had made up your mind that in the race created by you 
vertical displacement should be a factor in ''depth per- 
ception", how would you arrange your partner's eyes 
or what new eyes would 3^ou give him 1 

Cards 22 and 23 may elicit from your partner the 
remark that he is more ready to ''imagine" (that is, to 
call) the thing on card 22 "a slanting oval" and also 
to "imagine" the things on card 23 "three (two round 
and one square) wire hoops of equal size, but in perspec- 
tive" if he closes one eye than if he keeps both eyes open, 
in either case using the stereoscope. Why is j^'our part- 
ner more ready for perspective vision (for "looking 
thru" the world) if he opens onty one eye? In order to 
give the right answer to this question, you must first 
learn to give the right answer to the following question : 
What is the difference in meaning between saying ' ' The 
lateral displacement is now zero" and saying "There is 
no lateral displacement exi^sting"? 

You actually will have, Avithout needing for tliat any 
stereoscope (why not?), the same case as that of card 22 



72 PSYCHOLOGY DEMONSTRATIONS 

or 23 whenever you make your partner visit an exhibi- 
tion of paintings. Imagine that you are the artist whose 
paintings are on exhibition. It might be to your inter- 
est, then, to advise your partner to close one eye. Why ? 
When he visits your exhibition, are you very anxious 
to warn him against mistaking these wooden frames for 
window frames of some sort? Are you very anxious to 
keep him reminded that they serve to keep the pied 
canvases stretched flat ? Or would you rather have him 
forget all about those canvases and call them window 
panes ? 

There are some curious kinds of "stereoscopic views" 
for sale in high class toy shops.. With these kinds you 
do not look thru a "stereoscope" at all. With one kind 
you simply take the picture you have bought in your 
hands and look at it (apart from observing a certain 
rule about holding it) just as you would look at any 
picture. This kind is called "parallax-stereograms". 
With another kind you have to put on your nose a kind 
of spectacles differently colored for each eye. But 
again you hold — at least it seems so at the first glance — 
only one, and an apparently poorly printed, picture in 
your hand. This kind goes under the commercial name 
of " plastographical views". Ask the instructor for 
samples and explain how the stereoscopic effect is brought 
about in these cases. 

Before leaving stereoscopy, you might answer the, fol- 
lowing questions concerning the common stereoscope, 
which are not strictly psychological questions, but whose 
answers may aid you on various occasions in life. 

1. Since it is difficult to diverge or even parallel 
the eyes, why do the commercial makers of stereoscope 



STEREOSCOPY 73 

cards insist on making the distmice of tlie pictures from 
center to center greater than the interpnpillary distance? 

2. What is that shape of the glasses, put by the mak- 
ers of stereoscopes into these instruments, which does 
away Avith the difficulty spoken of in the previous ques- 
tion ? 

3. The makers of stereoscopes make the prisms so 
that the real axes of your eyes converge at a point a 
goodly number of rods distant from you. Why do those 
makers dislike to have your point of convergence nearer ? 
( Remember what kind of thing is usually photographed 
and viewed stereoscopically.) 

4. Having your point of convergence at such a dis- 
tance enforces an accommodation for the same distance, 
that is, makes you far-sighted. How does the maker of 
the stereoscope shape the prisms in order to overcome 
that far-sightedness of its user? (Inform yourself as 
to whether far-sighted people buy spectacles with convex 
or with concave glasses.) 

5. Why does not tlie dealer in stereoscopes simply ex- 
pect you to hold the photograph far enough from your 
eyes to suit your far-sightedness? (Why do not far- 
sighted people, when they want to read the newspaper, 
simply liold it as far from their eyes as the natural 
accommodation of their eyes calls for?) 

Pseudoscopy 

Pseudoscopy, as we use the term liere, differs fi-om 
stereoscopy, not by am- discrepancy of principles (you 
use the same rules already memorized), but merely by 
the fact that you make your partner look at a rf<il Ih'nuj 
instead of at a double picture of a tliiuu'. You may. 



74 PSYCHOLOGY DEMONSTRATIONS 

when you read that sentence, think for a moment : ' ' Well, 
that is then, nothing but what I do every moment of my 
life, having always real things before my eyes.'' True, 
— but for pseudoscopy it is necessary to have an optical 
instrument which you do not have every moment of 
your life. This instrument is generalizingly called a 
''pseudoscope". The word "generalizingly"' is em- 
phasized in the last sentence because you cannot go 
into a store nor even into a laboratory of physics and 
ask for a pseudoscope. That would be like going into 
a drugstore and asking for a ''beautifier". There are 
many very different optical instruments which can be 
used to make a thing look ''pseudoscopic". You will 
handle bere only a few of the simplest ones. 

Take first the so-called ''total-reflection pseudoscope". 
Do not permit yourself to be confused by the word 
''total". That is a (physicist's) term which to jou, 
here, is entirely irrelevant and onh^ serves to charac- 
terize commercially the pieces of glass thru which you 
have to look. If you want to buy these pieces of glass, 
you have ta order them under the commercial name 
of "total reflection prisms". 

The best things ("real things") to use as objects to 
look at thru a pseudoscope are such things that, and 
placed in such situations that, neither the habits illus- 
trated on page 241 nor the habits mentioned on page 244 
of the text have a likely chance to function. In order 
to subdue the former, it is especially advisable to use a 
thing no part of which hides or shades any other part 
of it, and which is known to exist in this world in re- 
versible forms. A bouquet of flowers, for example, 
would not serve at all, for some of its flowers are partly 



PSEUDOSCOPY iiy 

hidden by others. Neither Avould a sculptured bust serve, 
for a huiuan head appears always convex, never con- 
cave, and is therefore not reversible. But the hollow 
truncated cones, which we have already used, will serve 
very well, provided they are not placed so that one part 
hides another part, and provided the illumination is so 
diffuse that no part appears conspicuously shaded. If 
the illumination is troublesome, a model made of black 
wire and placed before a white wall is preferable. — In 
order to avoid the habits (p. 244) based on accommoda- 
tion and convergence, it is advisable to avoid moving 
the eyes, that is, to keep the gaze fixed on a definite 
point while using the pseudoscope. 

The simplest and best object to look at, however, con- 
sists of three cardboard targets, about two inches square 
(so far as they are visible), of different colors, so that 
one may easily speak of each under its color name, and 
also of sufficiently different size to avoid the suggestion 
that they are meant to l)e alike. Place these targets on 
a little table (say, fifteen inches square) which stands 
about five, feet above the floor and which bears on its 
front a strip of wood or cardboard high enough to make 
it impossible to see the table surface on which the tar- 
gets stand. Place the three targets in echelon so that 
none of them hides any part of any other, and one of 
them about four inches, one about eight inches, and one 
al)out twelve inches from the front of the table. 

(rive your partner the orders and questions of the 
following paragraph. These are not psychological ques- 
tions at all, but are intended oidy to make him familiar 
with the instruineiit and to get tlie instrument adjnstcd: 



76 PSYCHOLOGY DEMONSTRATIONS 

^ ' ( 1 ) If the distance between tlie prism tubes from 
center to center differs gredtly from your interpupillary 
distance, move that prism tube which is fastened in a 
slot after you have loosened the bottom screw. But this 
adjustment is probably already made when you receive 
the instrument. Therefore, do not play with it. (2) 
Understand that the small round openings of the instru- 
ment are meant to be placed next to your eyes. (3) 
Look at the instrument from above and make sure that 
the prism tubes are approximately parallel. The screw 
on the right will set them parallel without any risk. 
(4) Look now with one eye only (closing the other eye) 
and convince yourself that by turning the prism tube 
within the larger tube holding it you can tilt the target 
table. (5) How many degrees do you have to turn the 
prism until the table appears upside down? (6) How 
much more do you have to turn in the same direction 
in order to make the table appear upright again? (7) 
Close the one and the other eye alternately and make 
sure that the prisms make the table appear exactly up- 
right to either eye. (8) Look at a small object (a pic- 
ture or a light fixture) on the wall ten or more feet 
away. With both eyes open turn the screw on the right 
until you see that small object clearly double; then 
turn the screw back until both those identical objects 
exactly coincide and leave the screw from, noAv on alone. 
You and the instrument are now ready for our psy- 
chological demonstration. ' ' 

After having done all this to your partner, tell him 
to stand five or ten or more feet from the target table 
and to look thru the pseudoscope at the table. In all 
pseudoscopy demonstrations, if your partner ordinarily 



PSEUDOSCOPY 77 

wears glasses, make liiiii wear liis glasses. Tell him to 
keep his eyes on one of the targets (remember page 244) 
no matter what questions you ask him about the others. 
What are the reasons for keeping the gaze constant in 
every pseudoseopy demonstration? Ask your partner, 
now, which of the targets, using their color names, he 
would call the nearest and which the farthest. Write 
down his answer. 

Tell your partner, then, to look at a person's profile 
alternateh' with the naked eye and thru the prisms and 
to tell you ivhat such a prism really does to the image. 
Now look at page 258 of your text. Suppose that you 
had made the two drawings I and II looking with the 
naked eye, and that you had then made the drawings 
III and IV after looking at your finger and pencil thru 
such a prism. What would III and IV then appear like ? 
Redraw in your note book III and IV in accordance with 
your partner's answer to the question what such a prism 
really does to the image {profile). 

Is it clear, then, that j^our partner could not help (if 
his targets were a finger and a pencil) saying about the 
distance of the finger exactly that which nor mall h/ he 
would say about the distance of the pencil f 

Human beings have this advantage over animals that 
they can ''generalize" (some call it "reason"). Before 
you contiiuie reading this manual, look up the page 
headings of pages 365 and 869 of your text. Let us 
see now liow well you can "handle words". Let us see 
if, instead of making a concrete demonstration by put- 
ting the above question to your partner ("whicli of 
tlie colored targets, seen thru the pseudoscope, he would 
call the nearest and which the farthest'') ^•ou couhl 



78 PSYCHOLOGY DEMONSTRATIONS 

have derived his answer by merely handling words (by 
^'reasoning"). 

Take the two paragraphs, the one beginning with 
' ' Experience ' ' on page 258 and the one ending with ' ' vi- 
sion" on page 259. Count how many times the words 
'^ right" and ''left" appear in each paragraph in each 
of two significant connections. . 

Notice that these words appear in two different con- 
nections, sometimes in connection with "eye", some- 
times in connection with ' ' to the ' ', meaning in the latter 
case lateral direction. Now, did yon ever take your 
partner's eye out of the socket and put it in the other 
socket? Not at all. Therefore do not do anything to 
the words ''right" and "left" in the two paragraphs 
whenever they appear connected with "eye". But when 
they appear connected with "to the" you should ex- 
change "right" and "left", if your partner uses an 
instrument that "changes the profile". 

Now make your partner handle the words "right" 
and "left", exactly as prescribed, in the first paragraph 
after the words "mig^t be called". That is, make him 
rewrite that passage which is in quotation marks in his 
note book in its new formulation. Compare the result 
wdth what the unaltered second paragraph states. Do 
you see now the agreement between your former con- 
crete demonstration of your partner's actions and his 
l^resent abstract reasoning {handling of words) f 

Your partner's abstract reasoning, quite aside from 
its value as exemplifjdng the discussion of chapter XVI 
of your text (by the way, what is the title of that 
chapter?), has a direct value for you in suggesting an- 
other kind of concrete demonstration of pseudoscopy by 



PSEUDOSCOPY 79 

means of another instrument to be put before his eyes. 
]\Iake your partner, for a change, rewrite again that 
same passage of the first paragraph in question. But 
make him rewrite it this time by doing nothing with 
the words ''right" and "left" when they appear con- 
nected with "to the", but by exchanging "right" and 
"left" whenever they appear connnected with "eye". 
Compare the result with what the unaltered second 
paragraph states. Do you expect from this mere reason- 
ing {handling of words) that you will again succeed in 
a concrete demonstration of pseudoscopy by means of 
a new method ?^ 

For this demonstration, then, it is necessary to remove 
at least one of the eyes from its socket. Let us, ivithout 
breaking any of the nervoiis connections^ remove your 
partner's left eye and put it several inches to the right 
of his right eye, so that his so-called right eye will func- 
tion as a left eye (that is, on the other eye's left side) 
and his so-called left eye wdll function as a right eye 
(that is, on the other eye's right side). 

We slmll not, of course, perform this operation by 
means of the surgeon's knife, but simply by placing 
before your partner's left eye a little mirror which 
breaks the line of sight rectangularly and throws it to 
the right, and by placing a second, preferably larger 
mirror, on the right side of his head, but a little in 
front, in order to break the line of sight again. What 
he really sees of our target table with his so-called left 
eye is then that aspect which can be seen from the 
position of the larger mirror, that is, from a position 
on the right of his so-called right eye. Tlie so-called 
right eye then functions as a left^ eye in the stereoscopic 
sense. 



80 PSYCHOLOGY DEMONSTRATIONS 

Tell your partner to place his head so that his left 
eye has the little mirror in front obstructing the view, 
and SOI that at the same time the right eye sees the target 
table freely. Tell him, then, without changing the posi- 
tion of his head, to take hold of the larger mirror and 
swing it around its pivot until the target table appears 
clearly double, and to swing it back until the target 
table appears single. Your partner and the instrument 
are now ready for the psychological demonstration, the 
demonstration of his habits. Ask your partner which of 
the targets, using their color names, he would call the 
nearest and which the farthest. — The ''reason" for his 
answer you have known already for some time, even 
"before asking the question. That ''reason" was your 
very inducement for constructing this second kind of 
pseudoscopic instrument. Let us call this instrument an 
''eye transplanting" pseudoscope. 

The "reasoning", that is, handling of words, which 
you have employed and which has just been referred to 
again, ought to make it plain to you that all possible 
pseudoscopes must belong either to the one or to the 
other of only tivo chief classes. That is, either the profile 
of each eye's image is reversed in a lateral sense; or 
the profiles are left unaltered, but that of each eye is 
given to the other eye. No third class is thinkable co- 
ordinate with these two classes of pseudoscopes. 

If you are familiar with the appearance of images on 
the photographer's ground glass plate, this might sug- 
gest to you the construction of a third kind of pseu- 
doscopic instrument, subordinate to the first of the two 
classes just mentioned. Ask the instructor to show you 
a "lenticular pseudoscope", and use it on your partner. 



PSEUDOSCOPY 81 

Now try again a little ''reasoning". In the first of 
those two paragraphs on page 258, make your partner 
exchange the words "right" and ''left" everytvhere no 
matter what their connection. How does the resulting 
statement compare with the unaltered statement of this 
same paragraph, and how with the unaltered statement 
of the other paragraph ? Do you expect your partner to 
act "pseudoscopically" in such a case? 

You can make the demonstration corresponding to 
this "reasoning" by giving your partner both a pseu- 
doscope of the first class and a pseudoscope of the second 
class to look thru at the same time, in combination. 
(You can also make the demonstration by standing your 
partner before the target table so that a mirror on the 
wall is about half way between him and the table and 
parallel to the line running from him to the table. Then 
make your partner see the table, not directly, but in the 
mirror. If you are fond of geometrical drawings, prove 
that you have then a combination of both pseudoscopic 
effects, that is, a double reversal of habits and thus no 
change of habit at all. But if you are not fond of geo- 
metry, we do not require you to do it.) 

Now select whatever pseudoscope you have come to 
like best and let your partner look at the truncated hol- 
low cone with which you are already familiar. Ask him 
if the pseudoscope doe5 not make the cone (quite aside 
from the pseudoscopic effect) more deserving of the 
name of (whatever the case may be) either "nearly 
cylindrical" or. "nearly funnel-shaped" than it would 
normwlly be. Explain that fact by recalling what you 
learned from demonstration X. (What changes in "size" 
make a funnel out of a cylinder?) 



82 PSYCHOLOGY DEMONSTRATIONS 



XV. Bright-Darh, 

Read to your partner what you find about the Bright- 
Dark substance (or Black-White substance, — it means 
the same) on page 264 of your text. Then cut out of 
black paper a parallelogram about an inch or two wide 
and about four inches long. Then cut from the center 
of this a smaller parallelogram so that a kind of black 
frame of about l^ inch solid width remains. Fold 
the shorter pieces (the ends) of this frame upon them- 
selves to stiffen them. Then fasten one of the long 
pieces of the frame with pins upon black velvet cloth 
lying on the table, and bend the other long piece slightly 
up so that you can easily slip a piece of paper under it. 
Put a pin in the center of the frame and order your 
partner to look steadily at the pin-head and to continue 
doing that no matter what you do or ask him. 

While he is thus engaged, slip a piece of white paper 
larger than the frame under the free half of the frame, 
aboutj as far as that pin-head. Slip out the white paper 
again. Slip it under again. And so forth repeatedly. 
See if you can do this fast enough or slowly enough — 
experiment! — to induce your partner to say that the 
one half of the frame ''differs" from the other half ''in 
darkness" w^henever the white paper is slipped under. 

What statement made on page 264 is demonstrated by 
that action of your partner which you have just called 
forth by your manipulations and your questioning ? 

What two regions of the large part of the moon un- 
illuminated by the sun — compare page 263 of your text 
— correspond to the one and the other half of your dark 
paper frame? 



BRIGHT-DARK 83 

In spite of the "opposition" of the Dark (or Black) 
excitation and the Bright (or White) excitation, these 
excitations are not antagonistic to each other in the 
sense that one would cancel or destroy the other and 
the one alone would be left. On the contrary, they 
are capable of coexisting in one and the same sensitive 
cell, as can be proved by the fact that in such a case 
the name of "similar" can, in comparison with the cells 
where they coexist, be applied to both the excitations in 
sensitive cells where the Dark excitation alone occurs 
and the excitation in sensitive cells where the Bright 
excitation alone occurs. You will now demonstrate this 
on your partner. 

Take a small disk of, say, 2% inches diameter and of 
rather dark (vulgarly speaking black) paper. This will 
serve as the stimulus for those sensitive cells where you 
want the Dark excitation alone to occur. Put this disk 
on another disk of 4 inches diameter and composed of 
a black and white sector. Put this combination of the 
21^ inch and the 4 inch disk on a third disk of 5i/2 inches 
diameter and of white paper. The white ring left free 
of this largest disk will serve as the stimulus for those 
sensitive cells where you want the Bright excitation 
alone to occur. When you spin the set, you give your 
partner three rings to look at. The smallest disk also 
appears as a ring, for the brass screw of about 1 inch 
diameter covers the center. Each of these three rings 
is about % inches wide. 

The middle one of the three rings is the one about whieli 
we asserted that your partner might call it similar to 
both the outer, bright ring and the inner, dark ring. If 
our assertion is true, we can also express it by saying 



84 PSYCHOLOGY DEMONSTRATIONS 

that ''obviously the two excitations Dark and Bright in 
spite of their opposition, the first mentioned fact, are 
not antagonistic in the sense of exclusiveness, but, second 
fact, are capable of coexisting in one and the same sen- 
sitive cell. 

Demonstrate this on your partner by instructing him 
to adjust the white sector and the black sector of the 
middle ring until he is willing to say that the result is 
equally similar (or equally dissimilar) to both the white 
and the black ring, that is, until he can no longer say 
that the resulting gray resemhles one of the two other 
rings less than it resembles the other. It is clear that, 
as soon as your partner has called the gray "equally 
similar" to the white and the black, he has also ad- 
mitted that it is perfectly sensible to call it ''similar" 
to the white and the black. 

Recalling again what you did in demonstrating the 
"opposition" of the Dark and Bright excitation, you 
ought to impress upon your memory that this "opposi- 
tion" goes among psychologists often under the name 
of Dark-Bright contrast, and also under the name of 
Dark-Bright indiiction. Adopting the latter term, you 
can restate the description of the demonstration just 
made on your partner with the rings of the color-wheel, 
by saying that the Bright excitation and the Dark ex- 
citation "mix", or that a gray is "a mixture" of color- 
less dark and bright (or "a mixture" of black and 
white), in spite of this mutual induction. You may 
wonder why your teacher or the author of this text 
makes such a statement, which is "so obvious". You 
will convince yourself in demonstration XVI that this 
is "not so obvious", for you cannot state the same for 



BRIGHT-DARK 85 

the Blue excitation and the Yellow excitation. You 
will find there "no mixture" because of the mutual in- 
duction. 

Read now the first paragraph on page 290 of your 
text and demonstrate, together with some of those facts 
which you have already demonstrated, the ''negative 
after-images", so-called, resulting from exposure of your 
partner's eye to black and white papers. (The "posi- 
tive after-image" you will study in a later demonstra- 
tion.) 

Place a large sheet of white paper on the table. 
Place the two^ halves of a sheet of black paper of similar 
size so that between them a strip about half an inch 
wide of the white paper is visible. Place a pin-head or 
other small object on the white strip as a fixation mark 
for your partner's eyes. Now let your partner keep 
his eyes steadily on that mark for a considerable time. 
When he tells you that the black is no longer as dark 
as it was at the first moment (compare "general adap- 
tation" on page 291 of your text), remove the black 
sheets. Ask your partner, before, not to move his eyes 
from the mark if you should move the black sheets. Ask 
him, now, while he keeps his ej^es on the mark, to de- 
scribe the appearance of the narrow strip. The nega- 
tivity of the after-image of the narrow strip ^Wll prob- 
ably be quite clearly expressed in the words which he 
uses. Proceed in the same way except exchanging the 
relative positions of black and white. Do both these 
experiments over, but leave the papers untouched and 
simply make your partner, when he has exposed his 
eyes long enough, cover his eyes with his hands and 
describe (with a little patience) the appearance of the 



86 PSYCHOLOGY DEMONSTRATIONS 

after-image of the narrow strip. In .order to give your 
eyes a chance for rest, you and your partner may make 
these experiments alternately on each other. The nega- 
tivity of the after-excitation in these cases is theoretical- 
ly much less plausible than the negativity of the ' ' succes- 
sive induction" phenomena in demonstrations XYI and 
XYII, where you will have true antagonism, while 
between the Dark excitation and the Bright excitation 
there exists, as already stated, no true antagonism, but 
only a peculiar opposition. 

X.YJ, The Antagonism of Blwe and Yellow. 

Read the lower half of page 277 and the whole fol- 
lowing page of your text and then proceed in exactly 
the same manner in which you proceeded in demon- 
stration XV making up of black and white three equal- 
ly broad rings, with this difference only that you use 
blue instead of black and yellow instead of white. 
Instruct your partner to adjust the sectors of the mid- 
dle ring until he is willing to say that the result is 
equally similar to both the blue and the yellow ring. 
You will observe that he can not carry out your in- 
structionS; that he will never say that the result is 
similar to both the blue and the yellow. He will al- 
ways call it (more or less) similar either to one or to 
the other, but never to both, — never both yellowish and 
bluish. However, he can be made to say that the re- 
sult is similar to neither the blue nor the yellow, that 
iS; that the middle ring no longer deserves the name 
"bluish" nor the name "yellowish" either, while hav- 
ing a certain adjustment of its sectors. Let your 
partner find this relation of the sectors and, in order 
to have a definite record of what your partner has 



The Antagonism of Blue and Yellow 87 

done, measure in hnndredths the relative size of the 
tAVO sectors. 

Now try to demonstrate on your partner what is de- 
scribed on page 274 and on page 275 as far down as 
^'general adaptation". After having done this with a 
large sheet of yellow paper, repeat the demonstration 
with a large sheet of blue paper. 

Read next the last two paragraphs on page 276 of 
your text and try to demonstrate the facts mentioned 
there. Put a piece of yellow or blue paper, two or three 
inches in diameter, on a fairly colorless (fairly "neu- 
tral", as we may also say) table and observ^'e whether 
your partner acts as your text states. 

Now repeat the last demonstration with tliis differ- 
ence. Fill the whole field of vision absolutely with 
only one color, either yellow or blue. You can do that 
best by taking a box, a little larger than your partner's 
head, but having both the bottom and the lid removed. 
For the bottom substitute a piece of transparent colored 
glass. Then make your partner put his face into the 
box while holding the box up conveniently with his 
hands. Cover box and head with a large black cloth, 
in the pliotographer^s manner, in order to keep your 
partner from seeing anything reflected on the glass, for 
reflected rays are not changed (filtered, colored) by 
the glass. Then let him look out thru an open ^dndoW 
upon a landscape containing houses, trees, streets and 
a variety of other things. Wait patiently until your 
partner has the experience, already demonstrated, of 
"general adaptation". That is, you wait until he re- 
ports that the originally quite discolored landscape be- 
gins to look natural again. Then take the wliole box 
away and at that moment ask him whether the land- 



88 Psychology Demonstrations 

scape immediately became discolored again, and in 
what coloring. You have thus demonstrated again 
''successive induction". (By the way, do you recall 
what other term, synonymous with successive induction 
and found, for example, on page 291 of your text, you 
used in demonstration XV?) 

Read next page 277 of your text. Take a large gray 
disk and place another disk, less than half the size, 
and either blue or yellow, on the gray disk. Then 
spin the whole set on the color-wheel. Instruct your 
partner to keep his eyes steady on the center of the 
wheel and to report to you the marginal effect on the 
large gray ring. 

Then demonstrate the same fact in such a manner 
that two opposite margins overlap. Take a yelloW 
and a blue piece of paper, of note paper size or larger, 
and let the edge of one lie on the other paper so that 
there is nothing between the two colors. Then take 
several strips of neutral gray paper, about % oi* %6 
of an inch wide, some darker, some brighter, prefer- 
ably cut in zigzags or serpentines rather than straight, 
and place them so that half of each is on the one, and 
half on the other color. Cover the whole with tissue 
paper and ask your partner what color names he would 
give to those strips, and whether these names apply 
only to the margins. 

Demonstrate the same fact again as follows. Take a 
yellow disk of 3i/4 inches diameter and place it on a 
disk of 4 inches diameter composed of a large black 
and small white sector. Then place the combination 
again on a yellow disk, of 5i/2 inches diameter, or lar- 
ger. Spin the wheel and ask your partner what color 
name he would give to the narrow ring composed of 



The Antagonism of Blue and Yellow 89 

e. black and white sector. Let your partner adjust these 
sectors to each other until he is more ready than ever 
to apply that color name. Then spin on a second color- 
wheel a combination of black, white, and blue sectors 
of any size disk, and have your partner adjust the 
sectors so that he would call the color on this second, 
solid-faced wheel a perfect match to the color of that 
narrow^ ring on the first wheel. Measure, in hun- 
dredths, the sectors of the second color- wheel and reoord 
the values in your note book. You thus get a measure- 
ment of the strength of the induction. 

Do again what you were told in the last paragraph, 
only using blue instead of yellow. By what names is 
this phenomenon referred to in the middle of page 291 
of your text? 

Repeat the last two cases, of a narrow gray ring on 
a yellow or blue background, with very unsaturated 
colors. For example, instead of two saturated yellow 
disks use two disks of which each is a lil^e combination 
of only 25 per cent yellow and 75 per cent gray. Use 
a gray of a brightness (of a ''.darkness", if you pre- 
fer to say so) as near as you can find in the laboratory 
gray paper disks dike the brightness (darkness) of 
the colored paper with which jo\Ji desire to combine it. 
Spinning the wheel and matching the narrow ring's 
color on a second wheel showing a solid face, how mucli 
blue do you need on that second wheel ? IMeasure. You 
will be surprized when yom compare this witli your 
previous result at the strength of the color induction 
even when the inducing color is rather unsaturated. 



90 Psychology Demonstrations 

XVII. Red-Green and the Entire System of "Sights''. 

That wliicb ''sounds" we call ''a sound". We need 
in psychology a simple term for that which "looks". 
Let us, as the heading suggests, call it ''a sight". 

Proceed exactly as you did in the first paragraph of 
demonstration XYI, except that you substitute red 
for blue and green for yellow. Let your partner ad- 
just the sectors of the middle ring until this ring is no 
longer called by him reddish nor greenish either. Then 
lemove the largest and the smallest disk and retain 
only the middle size disk composed of a red sector and 
a green sector. Ask your partner if that ring, after 
having thus become a Avhole disk which is neither red- 
dish nor greenish, can be called colorless, a neutral gray. 
If he replies in the negative, ask him furtlier whether 
he would prefer to call it yellowish or bluish. If he 
prefers the former, give him a blue disk of the same 
size (if he prefers the latter, then, of course, you give 
him a yellow disk, — always the antagonistic color) and 
let him add it as a third sector to the other two sectors, 
the red and the green. 

Now place the disk, composed of red, green and that 
third color on a larger colorless disk of, say, 5% inches 
diameter, composed of a white and a black sector. Spin 
the whole and show your partner the gray ring sur- 
rounding an inner, more or less colored field. If every- 
thing you have learned theoretically about your part- 
ner's visual sense (read especially page 281 of your 
text) is correct, it must be possible to adjust the white 
and black so to each other and also the inner three 
sectors so among themselves that he will call the whole 
disk, when spun, "homogeneous". Let him very care- 
fully and patiently make these adjustments; and then 



The Antagonism of Red and Green 91 

measure the five sectors and write the result in your 
note book in order to have a record of what you have 
here demonstrated about the relation of the Red-Green 
substance to the Blue-Yellow substance. 

Read now the lower half of page 283 and all of page 
284 of your text and then give your partner the four 
(Wliy not six? And why is this question asked?) 
tasks, one after another, of producing on the color wheel 
a dual color, in a middle ring, so that this dual color 
resemMjes equally (no more nor less one than the other") 
its two singular colors which are to appear on the in- 
ner and on the outer ring. Choose the disks so that the 
three rings are approximately of equal width. For ex- 
ample, use diameters of 2%, 314, and 4 inches, or of 21/0, 
4, and 5V2 inches. When your partner pronounces the 
resemblance equal, measure the sectors for your rec- 
ord and proceed to the next of the four tasks. 

Read now page 285 of your text and proceed to 
demonstrate on your partner the necessity of using for 
The representation of the entire system of ''sights" a 
graph or model of three dimensions. In order to dem- 
onstrate this you must obtain a small disk of a satu- 
rated color (choose a dual color, in order to get rid 
of the idea that for demonstrations of the system of 
"sights" you are restricted to the use of singular col- 
ors) ; place this on a larger disk composed of two sec- 
tors, one of the same saturated color and the other sec- 
tor a gray neither much darker nor much lighter than 
it; and place this set again on a larger disk of the same 
gray. The absolute size of the triple disk does not mat- 
ter; but make the three rings approximately eiiually 
Avide. Spin. Ask your partner to locate that line (that 
is, the two end i)oints of th.at straight line) on whi^'li 



92 Psychology Demonstrations 

the three ^'sights" of your color-wheel are ideally found 
in the three octahedrons of your text and also in the 
painted and hollow model in the laboratory. 

In the preceding paragraph, however, you have not 
yet demonstrated the necessity of using a graph or model 
of three dimensions. Your partner could still locate 
every name used by him within the color square. But 
give your partner now two black disks to substitute 
for the two gray disks of the preceding paragraph and 
let him spin these on the color-wheel ; give him also 
two white disks aud two colored disks as before, to 
spin on a second color-wheel. Ask him to vary the 
sectors of the middle ring on both wheels to suit, himself 
and then to locate the line for the one wheel and for the 
other wheel on which the ''sights" of each w^heel are 
ideally found in the octahedrons and in the model. Now 
he can abstain from using a, third dimension of the 
graph or the model only if he is willing to restrict him- 
self to the single chosen color. In the preceding para- 
graph he remained within two dimensions no matter 
how many different colors he desired to use. 

Before you dismantle the two wheels used in the last 
paragraph ask your partner whether the coloring of 
the middle ring is as easily detected in mixing 10 per 
cent color with 90 per cent black as in mixing 10 per 
cent color with 90 per cent white. 

Now read the last paragraph of page 286 of your 
text. Ask the instructor for a gray screen with a half 
inch hole and a horizontal scale (a campimeter or peri- 
meter) ; also for a head-rest, a pointer, and four sheets 
of paper : orange, violet, olive, and peacock. Fix your 
partner's head so that, if he now looks thru that hole, 
he sees the space of the hole completely filled in with 



The Entire System op Sights 93 

tlie color of one of those sheets. The sheet must l.^e 
well illuminated and have no shadow on it. Therefore 
keep yourself as well as other things out of the liglit. 
Arrange the gray screen so that its scale lies on the 
I'ight, provided your partner intends to use his right 
eye; think it over and convince yourself that, other- 
v,dse, when your partner looks at different points of 
the scale, the hole might fall on the blind-spot of his 
right eye. Let the perpendicular distance from the eye 
to the campimeter be about six inchesi and keep this 
distance constant during all the tests. 

Now ask your partner to close liis left eye and to turn 
his right eye along the scale until the hole becomes in- 
visible. Put your pointer at this point of the scale and 
move it slowly along the scale toward the hole until 
your partner, who follows your pointer ivith his eye, and 
who is not permitted meanwhile even to glance at tlie 
1.1 ole, tells you that the hole has not only become visible 
(it will first appear as a neutral gray), but that it has 
just taken on a definite singular color. Record that 
point of the scale in your note book. 

Continue movmg your pointer with a speed whicli 
your partner finds agreeable, until he tells you that the 
hole has just taken on the dual color to be expected. 
Record that point of tlie scale. 

Repeat the same procedure with the other three sheets 
of colored paper which we selected. 

Now put your pointer near the hole and ask your 
partner, who follows the pointer with his eye, to stop 
your motion of the pointer receding from the hole by 
telling the very moment when the dual color changes 
to a singular color. Record the distance from tlie hole 
as measured on the scale. 



94 Psychology Demonstrations 

Continue moving your pointer at a suitable speed 
until your partner tells you that the singular color 
of the hole has just given way to a neutral gray. Rec- 
ord that point of the scale. 

Repeat the same procedure with the other three sheets 
of colored paper. 

Take now the average of the eight scale points at 
which the changes occurred between a dual and a sing- 
ular color. Take further the average of the eight scale 
points at which the changes occurred between a singular 
color and a neutral gray. These two averages give you 
an idea of the relative extent of the inner area of the 
dual colors and the surrounding area or zone in which, 
only the singular colors blue and yellow are easily 
recognizable. 

That the eight measures giving each average vary 
as much as you will probably find them to vary, is due, 
^imong other facts, to the fact that the Red-Green sub- 
stance and. the Blue- Yellow substance do not have a 
very sharp border line, but fade out somewhat gradually 
from more central to more peripheral parts of the re- 
tina. 

If you have a clever partner and are yourself clever 
enough, you may devise a method of demonstrating also 
the fact that, when a dual color stimulus passes out of 
your partner's blind-spot, he is likely to give it first the 
name of a singular color and then only the name of a 
dual color, just as on the passing of a stimulus from 
the peripheral to the central regions of the retina. But 
this demonstration is much more difficult and we do not 
urge you to undertake it. 

Now we are going to give you six tests in order to find 
out what you have learned in demonstrations XY, XYT 



THE ENTIRE SYSTEM OF SIGHTS 95 

aud XVII about Imiiiaii reactions to qualitatively vail- 
ing sights. Perform the following- six tasks and tell 
m your note book exactly how you performed them. 

(1) MatcJi in darkness-hrigJitness two ecjually broad 
iiiigs of the color- wheel, — 'One ring being any (singular 
or dual, to suit yourself) saturated color which happens 
to be a rather dark color whenever saturated, aud the 
other ring being such an unsaturated color (singular or 
dual) as happens to be a rather bright color whenever 
saturated, but which you have darkened by the addi- 
tion of a black sector for the sake of matching. 

(2) Match iin darkness-hrigJitness two equally ])road 
rings of the color- wheel,^one ring being any (singular 
or dual) saturaited color which happens to be a rather 
bright color whenever saturated, and the other ring 
being such an unsaturated color (siugular or dual) 
as happens to be a rather dark color whenever satur- 
ated, but which you have brightened by the addition, 
of a white sector for the sake of matching. "Why is 
the regular octahedron only an approximation to tlie 
true form of the color pyramid? 

(3) Let three equally hroad colored rings of the 
color wheel dijfer only in darkness-hrightness (not dif- 
fer also in coloring nor in saturation either) . Use for 
the intermediate ring a 50 ^/^ sector of gray, for the 
inner and outer sector black (for either one) and white 
vfor the other sector), — black and white in (luantities 
to be fouud by matching the degree of saturation of 
the three rings. What quantities did you usef And 
on what line, parallel to what, iwe these three points 
in the octahedron? 

(4) Repeat what the last paragrapli instrueted you 
to do, with this exception that, if you used thicn <m siiii^ii- 



96 PSYCHOLOGY DEMONSTRATIONS 

lar color, use now a dual color; or, if you used then a 
dual color, use now a singular color. 

(5) Let three equally hroad rings differ strikingly 
in color, but not at all in darkness-brightness ; and pay 
no attention whatsoever to the question how saturated 
the colors are, save that one (only one) of the rings 
must have its maximum, of saturation. 

(6) Repeat what the last paragraph instructed you 
to do, with this exception that, if you used then a ma- 
jority of singular colors among the three, use now a 
majority of dual colors; and if you used then a major- 
ity of dual colors, use now a majority of singular colors. 

XVIII. Some Ghosts. 

It goes without saying that the marginal effects of 
local adaptation, and still more the negative after- 
images, and most the positive aifter-images have been 
occasions, in the history of mankind, for "seeing 
ghosts". A person who stares at another person (re- 
member what you have learned in demonstration V and 
on pages 249 and 291 of your text as to whether such 
a functioning of human eyes is normal or not) may 
very Avell see the other person surrounded by an ''aura". 
An after-image is still more likely to be regarded as 
iv ghoist by superstitious people than a simultaneous 
outer margin of a person's figure. Therefore the title 
of this chapter. Demonstrate now a few particularly 
striking cases of successive induction of sights. 

Take your partner into a room which has only one 
Avindow. Let him look steadily for about a minute at 
the window cross or simply at a definite point of the 
cross-bar of the two sashes if there is no cross. Then 
make him cover his eyes with his hands, 'keep his eyes 



SOME GHOSTS 97 

steady, and report, to you duriiij>: the next minute what 
thing's there are visible. Now read the last paragraphj 
on page 290 and the first paragraph on page 291 of 
your text. If your partner has not reported to you 
everything mentioned there, repeat the experiment and 
iriake him look at that mndow cross twice as long. 

Now take your i^artner into a perfectly dark room and 
keep hdm in the dark two or three minutes, until liis 
eyes have become sufficiently adapted. Then tell him 
to look in the direction in which he knows there is an 
electric fixture. Turn on the light of a single bulb, and 
after your par,tner has looked at it for a short time 
turn off the light again. Ask him to report whatever 
there is now "\dsible, patiently. If his answers do not 
satisfy you, repeat again as in the preceding paragraph. 
AVliile still in the dark, move a glowing match in a 
circle or in other curves. Your partner's reports will 
help you to answer the question: ''Why do shooting 
starsi alwa^^s have a tail?" 

Now go to a dark room where you have a "Hering 
window", that is, no other illumination than that which 
comes thru two parallel narrow slots six or twelve inches 
apart, one having a colored, the other a ground glass 
pane. Use a parallel ruler and throw four shadows, 
close together, on a white or gray sheet of paper con- 
veniently arranged opposite the window. Two of these 
shadows (which?) ought to be colorless; but they are 
not. And the ghost-like aspect of the case consists in 
the fact that, if the relative width of the window slots 
is well adjusted to the transparency of the glass, your 
partner can not tell which two of the four colored 
shadows are the real things and which two are the 
ghostS'. So you see thiat there mav be some excuse for 



98 PSYCHOLOGY DEMONSTRATIONS 

the reports of some people in the histoiy of mankind 
that ghosts had mally made their appearance. 

A somewhat similar and again very striking dem- 
onstration is that made with the rings in the box which 
you will now obtain from yonr instructor. Some of 
these rings are strongly colored because no white light 
is reflected on them. They are, so to speak, shaded. 
Some others ought to be virtually colorless because no 
light C' no-light" equals black) is sent thru the light 
sifting and thus color producing glass. If these latter 
rings appear colored, they deserve to be called ghost 
colors. You will find again that your partner, if the 
adjustments are well made, can not tell which are the 
real colors and which the ghost colors. 

There is a summation of two effects, (1) the bright- 
dark opposition, or call it contrast, between the shaded 
and the non-shaded portions of the background, which 
becomes here a phenomenon of nervous deflection with 
consequent failure i:o react to the existing color exci- 
tation of the non-shaded background portions, and (2) 
local adaptation for the alternating rings. It is this 
summation which makes the ghosts in this case and even 
miore in that of the Herino- window so realistic. If 
there were an adequate motor reaction to the coloring 
of the whole background, too, the ghost would be 
much less realistic. 

XIX. Tone Induction and What it is Good For. 

When there are currents of electricity where nobody 
poured out any, we speak of electricity by induction. 
"When there is color according to your partner's testi- 
mony, altho you did not in any sense pour out any color 
there, you speak of color by induction. You miglit then 



TONE INDUCTION 99 

very well accustom yourself also to speak of tone by 
induction, when your partner reports the presence of 
a tone alt ho you did not pour out any such tone, while 
mdeed pouring out other tones. Electricity may in- 
duce electricity, color may induce color, tone may in- 
duce tone. 

Read to your partner what you find about tone in- 
duction in the last paragraph on page 307 of your text. 
Then sound the two Galton whistles by filling the large 
bellows completely with air and letting the bellows go 
do\^ai without working it, in order to avoid every dis- 
turbance by noise. Fill again and let down again. And 
so fortk The bellows, being large, gives air for a con- 
siderable time when completely filled. 

Sound a tuning fork (one of 300 full, so-called double, 
\ibrations will do) by tapping it gently with your finger 
or a felt hammer, and ask your partner to remember 
the tone. Let him hum the tone if he wishes. Then 
stop the fork by touching it, and make your partner 
change one of the whistles until the induction tone is 
just like the tone he was humming. He can not do 
tliat while the fork is sounding, because thie fork .tone 
would ''swamp" everything. There is no danger that 
your partner might confuse one of the two whistle 
tones ^^dth the induced tone. The latter, even if out of 
tune with the fork tone and much higher, is too mellow 
to be mistaken for the exceedingly high, very slirill, 
tones of the Galton wliistles. "Shrill", however, does 
not mean very loud, but "sort of pointed". Thus 
your partner's task consists only in lisfeuing to the 
induced tone and maMug it equal to fJic tone he was 
or is humming. 

By the way, if you have studied physics, wo must 
warn you against confnsino- a ('('rtain jiliysical phenom- 



100 PSYCHOLOGY DEMONSTRATIONS 

enon with what we have called an induction tone, that 
is, with an ''induced" sensory and nervous excitation. 
You find in the literature of physics frequent references 
to "combination tones, summation tones, difference 
tones, asymmetry tones" and other acoustic phenomena 
of a similar kind. These are all characterized by the 
fact that some iinsymmfietrical elastic body, a certain 
reed, a certain air volume, an auditory tympanum, an 
auditory oissicle in its peculiar bearings, etc., is forced 
at some time to vibrate with unusual vigor; and then 
certain phenomena occur, deducible from differential 
equations, not incomparable to the planetary aberra- 
tions of the astronomers. The not infrequent confusion 
is due to the fact that the induction tones are also a 
kind of difference tones. Look again at page 307 in 
order to tell why they may also be called difference 
tones. ) 

Since the induction tone is a kind of difference tone, 
you can tell by "reasoning" (remember chapter XYI 
of your text) that there must be a second position of 
the piston of the same whistle when the induction tone 
will.be exactly the same. Find that second position. 
Msike your partner turn the piston so that the induced 
tone becomes lower. Make him continue turning, very 
slowly, in the same direction, while he reports to you 
that the tonie becomes still lower, momentarily dis- 
appears, then reappears very low, then rises more and 
more and finally again equals the fork tone. Aside 
from being good practice for your partner and satis- 
fying your natural curiosity this procedure of finding 
the second position has no particular virtue. 

When the induced tone is well tuned and in unison 
with the fork tone, your partner ought to report that 



TONE INDUCTION 101 

there are "beats", provided the simultaneous fork 
tone is neither too strong nor too weak. The intensity 
lias to be tried out. They are irregular beats on ac- 
count of the slightly inconstant air pressure in a col- 
lapsing vessel made of wood and leather. Such slow 
beats may be used by your partner as an indication that 
he has about. finished what you asked him to do. Such 
slow beats are therefore of great practical value to the 
professional tuner of instruments. 

An interesting variation of this procedure, of dem- 
onstrating an induced tone hy having somehody tune 
it, is the following. You take two tuning forks, say, 
of 600 and of 525 (complete) vibrations. You bow these 
forks with a bass bow to make them sound very strong- 
ly and keep them sounding very strongly. This re- 
rjuires some skill in handling the bow without tearing 
the horse hairs by letting the hairs slip off the end 
of the tine which you are bowing. (You never touch 
more than one tine.) Keep at a safe distance (about 
1/2 inch) from the end of the tine. 

Now give your partner a big tuning fork with ad- 
justible weights, variable between, say, 60 and 100 vi- 
brations, and tell him to adjust the weights until the 
tone of this big fork is equal to the induction tone of 
the two smaller forks which you keep sounding. Do 
not separate the weights much from each other; if you 
do that, the fork will not sound well. Your partner 
should again utilize the beats, which in this case will 
fortunately be very regular, in order to notice thiat lie 
is approaching the goal which you have set for liim. 

Tell your partner to show, by beating the air with 
his finger, the exact tempo of tlie beats. Then let him, 
by tuning the big fork, slow up the tempo of the beat^ 



102 PSYCHOLOGY DEMONSTRATIONS 

until there are no beats left. This is good practice, 
helpful in the task of tuning at any later time any mu- 
sical instrument. 

Now let your partner apply his knowledge of the 
induction (''difference") tones to the very practical 
problem of finding the ratios in which the tones of the 
white keys of a certain stop of the laboratory organ 
are tuned. If we could afford to have you and your 
partner tune the organ, this would be still more inter- 
cepting. But since in all probability you would rather 
mistime it, we restrict you to finding out in lokat ratios 
it actually is tuned. Start with the ratio of a high f 
to the following g, and determine all the ratios as far 
as the next f. 

First sound steadily f and g simultaneously, and let 
your partner, listening to the low induction tone all the 
lime, discover what tone that induced tone is by mo- 
rn efitarily pressing down one of the white keys on the 
left of the keyboard. That is, your question is : If 
g — f = X, what is x? Your partner tells you. Then re- 
member that the ratio of octave tones is always 1 :2, 
and try to express x as a function of either f or g. As 
soon as you have substituted this in the above equation, 
you can, after dividing the whole equation by f, answer 
the question: What is the ratio g :f numerically? Your 
first problem is solved. 

Now sound steadily a and g, and let your partner 
discover what white key on the left of the keyboard is 
X in the equation- a — g=x. Then try to express x in 
this equation as a function of g (remembering the re- 
sult of the preceding paragraph, without which you 
could not do it). Divide the whole equation by g and 
ansAver the question: What numerical value do yon 
get for the ratio a:g? Your second problem is solved. 



TONE INDUCTION 103 

In a similar manner determine the ratios b :a, e :b, d :c, 
c:d, f:e. Yon will then have a definite idea as to 
l^ow an organ tnner wonld proceed, when the reeds or 
pipes are still nntnned^ bnt the ratios are given to him. 
Yon notice that the existence of the induced tone lias 
n high practical value. 

XX. Voiced and Voiceless Speech Sounds. 

The following demonstrations may be more striking 
if you can make them on your partner before he has 
read the following list of words. The demonstration 
may be quite successful, however, even if he has already 
lead the words in the list. Besides, it is always pos- 
sible for you to try the same demonstration on some 
friend who is not one of your classmates and who is 
unacquainted with the list. 

In order to : understand what you are going to dem- 
onstrate, read pages 313 to 319 of your text. 

Give your partner a sheet of paper and ask him to 
write down quickly, without, hesitation, the number and 
the word which he understands whenever you pronounce 
a cardinal number (from 1 to 50) and the word in the 
list belonging to it. However, instead of making him 
write the whole word, be satisfied if, in order to save 
time, he writes only the first two or three lettei-s, just 
enough for later identification. 

Now read to him the list, carefidly observing every 
condition lielow mentioned. (1) Be sure that you 
whisper, that is, that your larynx is wide open all the 
time and never offers the slightest avoida])le obstruc- 
tion to the passage of the air. (2) Do not try to sjicak 
loud, for, if you do tiy, you will surely uot wliispor. 
But be sure that you do not make the first souiul of 



104 PSYCHOLOGY DEMONSTRATIONS 

each word (corresponding to the black-faced letter) 
weaker than the following parts of the word. Rather 
give the hlack-faced part of the tvord more emphasis 
than the others. But remember always that the whole 
word is to be whispered. 

The experiment, in addition to its demonstrational 
yalue, will serve you as a test of yonr ability to carry 
out the instructions given above. The fewer errors 
;vour partner shows in understanding you, the less cap- 
able you are in following those instructions. 

Do not wait long after having pronounced each word. 
Give your partner barely time enough to jot down the 
iiumber and two or three letters before you give the 
next number and the next word. When you Have fin- 
ished the fifty words, compare your partner's list ^^dth 
your list of words. Mark in your partner's list all the 
words' misunderstood. A comparison, then, of the words 
misunderstood with those well understood ought to re- 
veal clearly what speech sounds (''letters", as we 
vulgarly say) of the English language can not be pro- 
duced unless they are voiced. 

I. smith 14. vile 

2. plumber 15. rooster 

3. carpenter 16. grow 

4. dinner 17. gill 

5. sick 18. joke 

6. veal 19. rope 

7. light ' 20. span . 

8. bride 21. stake 

9. write 22. dent 
10. woo 23. hound 

II. zeal 24. whip 

12. boast 25. wine 

13. letter 26. die 



VOICED AND VOICELESS SPEECH 



105 



27. 


bull 


28. 


bush 


29. 


meat 


30. 


eat 


31. 


junk 


32. 


mouth 


33. 


nose 


34. 


gin 


35. 


milk 


36. 


cheese 


37. 


girdle 


38. 


fish 



39. river 

40. Greek 

41. Chinaman 

42. Russian 

43. dirk 
4l4. fork 

45. knife 

46. apple 

47. gore 

48. furnace 

49. goal 

50. bowl 



Now tell 5^our partner that you are going to pro- 
nounce the sound of ten letters (be sure not to pro- 
nounce the ''names" of the letters, but their sounds; 
compare page 376 of your text) and that you want him 
unhesitatingly to write do\^^i, after each number from 
51 to 60, one word which either begins or ends (prefer- 
ably 'begins) ^nth that particular speech sound. Again 
you pronounce both numbei; and letter sound whisper- 
ing, with your larynx wide open. However, altho 
whispering, put a ccnsiderable degree of emphasis on 
each letter sound. Compare your partner's list of ten 
words with your list of letters and draw your own 
conclusions. Blow vour nose before vou start. 



51. V 

52. b 

53. w 

54. z 

55. ga 



56. 


J 


57. 


d 


58. 


m 


59. 


n 


60. 


ng 



Now tell your partner to write down three more words 
beginning or ending with the tliree sounds vou give 



106 PSYCHOLOGY DEMONSTRATIONS 

li.im. In this case yon not only whisper, hut also hold 
your nose tightly closed. 

61. m 62. n 63. ng 

And finally make him write one more word in the 
same manner. In this case, while you do not whisper ^ 
you hold your nose tightly closed. 

64. ng 



The stndent should carefully detach, when he needs 
them, the entry blanks following the index of this book, 
and use them in writing up the demonstration to which 
each belongs, pasting them (not pimiing or clipping) in 
the report which he hands in to his teacher. 



The Apparatus Needed for the Demonstrations described 
in this book is obtainable from C. H. Stoelting Co., 
3037-3047 Carroll Avenue, Chicago. 



INDEX 



Accommodation 34, 75. 
Adaptation 85, 87, 96. 
Adjusting 24, 25, 34, 49, 53. 
After-images 42, 85, 86, 96, 

97. 
Angles 45. 
Animals 16. 
Antagonism 86, 90. 
Antagonistic colors 66. 
Architecture 53. 
Artificial blind-spots 56, 59. 
Asymmetry tones 100. 
Aura 96. 
Average 7. 
Beats, use of, 101. 
Binocular vision 60. 
Black 82. 

Blind-spots 54, 93, 94. 
Brain 39. 
Bright 82, 95. 
Campimeter 92. 
Causes 11, Z7. 
Choice reaction 4, 8. 
Colors, antagonistic, 66. 
Colors, dual, 91, 93, 91. 
Colors, similar, 67. 
Colors, singular, 91, 93, 94. 
Combination tones 100. 
Competition, law of, 62-64. 
Compromise 18. 
Condensation, nervous, 36, 39, 

40. 
Conductivity 9, ctl , 39. 
Consciousness 2, 2>7. 



Contrast 84, 98. 

Convergence 75. 

Dark 82, 95. 

Definition of Psychology 25 

Deflection 25, 38, 64, 98. 

Delayed reaction 36-39. 

Depth 34-36. 

Deviation, average, 7. 

Difference tones 100, 102. 

Dimension 22. 

Dual colors 91, 93, 94. 

Duration 11. 

Ebbinghaus 11. 

Effect, law of, 11. 

Error 19, 20, 23, 2>2. 

External factors in habit 

formation 12-14. 
Eyeball 25. 

Eye movement 26, 48. 
Frequenc}', law of, 11. 
Ghosts 42, 96. 
Gloss 6o, 64, 66. 
Habit formation 9-14, 65. 
Habits 47, 49-51, 55. 56, 58, 

65, 69, 7S, 81. 
Hering window 97, 98. 
Illusion 22, 45-54. 
Imagination 59, 60. 
Induction, color. 84-86, 88. 89. 
Induction, tone. 98. 
Introspection 3. 
Kinesthetic 21. 
Knowledge 39. 
Earge-small 43-45. 81. 



10' 



103 



INDEX 



Larynx 103, 105. 
learning curve 15, 16. 
Localizing 22, 25, 27, 3 ', 35, 

54. 
Long path 9. 
Magic 6. 
Alaze 13-16. 
Mixture, visual, 84, 85. 
Multiple habit 9, 12, 13. 
Muscle tonus Z7.. 38. 
Neuramebimetc:r 5. 
Octahedron of sights 92. 
Opposition of bright and 

dark 83, 84, 86, 98. 
Painters 67. 

Parallax-stereograms 72, 
People 2. 
Perception 48. 
i^erimeter 92. 
Perspective 46, 47, 49, 51-53, 

71. 
Physiologist 25. 
Plastographical views 72. 
Preoccupation 2)7, 
Pseudoscopes, two classes of, 

80. 
Pseudoscopy 45, 69, 72. 
Psychanalj^sis 50, 51, 55, 64, 

65. 
Psychologist 25. 
Reaction time 4. 
Reading 26, 27. 
"Ready" signal 23. 
Real 97, 98. 
Reasoning 77-8L 
Reflex 9, 29. 

Repetition in learning 11. 
Resistance, nervous, 9, 10. 
Resultant, law of, 62. 



Rhythm 29. 

Rhythm test 30-32, 34. 

Rhythm training 32-34. 

Sense organs 25. 

Shooting stars 97. 

Short path 9. 

Sights 90, 96. 

Sights, system of, 90-92, 95. 

Singular colors 91, 93, 94. 

Size 43-45, 81. 

Sound localization 22. 

Space 45. 

Speech sounds 103. 

Stereoscope prisms 72, 72. 

Stereoscopy 68. 

Subdivided areas 53. 

Substituted action 45, 46, 
49-51. 

Summation tones 100. 

Susceptibilit}^ 9, 10. 

Teleology . 11. 

Threshold 16, 17, 19, 21, 41, 
42. 

Tones 98. 

Tones, practical value of in- 
duced, 102, 103. 

Trick 6, 20, 56-58. 

Tuner, instrument, 101-103. 

Vesture 53, 54. 

Visual localization 27, 34-36. 

Voiced sounds 104. 

Wasted habits and wasted 
reflexes 45, 52, 75. 

Weights 16, 17, 20. 

Whisper 103-106. - 

White 82. 

Will 39. 

Zones, color, 94. 



To page 15. 



















































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To page 23. 



Give each of the nine stiniuH al)out ten times in irregular 
cord each judgment by making a httle cross in the proper scjuare. 
sheet in your note book. Translate your records into the talile bcli 
make a general statement covering your results. 

JUDGMENTS 



ordei 



. Re- 
le llii^ 
l-iiialK 




1. Lefts (L, LF, LB) regarded as Rights (R, RB, RF). 

2. Rights (R, RB, RF) regarded as Lefts (L, LF, LB). 



times 
times 



1t< 



ital. 



.3, Fronts (F, RF, LF) regarded as Backs (B, RB, LB) or Above times.-) 

^Total 
4. Backs (B, RB, LB) regarded as Fronts (F, RF, LF) or Above times.] 

.5. Above called Fronts (F, RF, LF) or Backs (B, RB. LB) times. 

G. Above called Rights (R, RB, RF) or Lefts (L. LB, LF) tmus. 

T Above judged correctlj' . . . - . time?. 



To page 40. 



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24 




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22 




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23 




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21 




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20 




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20 




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19 




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19 




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9 




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9 




17 




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